Commit f81ce56b authored by chenzk's avatar chenzk
Browse files

vllm kvprune:v1.0.1

parent 2b7160c6
import logging
import math
import torch
import triton
import triton.language as tl
from compactor_vllm.utils.triton_compat import (
autotune as triton_autotune,
cuda_capability_geq,
maybe_set_allocator,
)
logger = logging.getLogger(__name__)
def causal_sparse_varlen_with_cache(
q,
k,
v,
k_cache,
v_cache,
seq_lens_bh,
global_page_table,
batch_mapping,
cu_seqlens_q,
max_seqlen_q: int,
max_seqlen_k_cache: int,
HKV: int,
PAGE_SIZE: int,
sm_scale=None,
):
"""
Causal prefill attention over a paged KV cache plus a block of newly
appended tokens in a packed batch format.
This function wraps the Triton kernel
``_causal_head_sparse_varlen_with_cache`` to compute prefill attention for
a batch of variable-length sequences, where:
• Past keys/values are stored in a paged global KV cache
(``k_cache``, ``v_cache``) with a (per-layer) page table.
• New tokens for this step are given as K/V blocks
(``k``, ``v``), together with a packed query block ``q``.
• The result is equivalent to applying causal attention over the
concatenation of:
[ cached KV prefix || (K_app, V_app) for this step ]
for each sequence in the batch.
Grouped-query attention (GQA / MQA) is supported by allowing more query
heads than KV heads: ``HQ`` must be divisible by ``HKV``.
Args:
:param q:
Query tensor of shape ``[N, HQ, D]`` (float16 / bfloat16/float32).
``N`` is the total number of new tokens across the batch
(i.e. ``N = sum_b seqlen_q[b]``), packed according to
``cu_seqlens_q``. ``HQ`` is the number of query heads, ``D`` the
head dimension (must be a power of two).
:param k:
New key tensor of shape ``[N, HKV, D]`` for the same tokens as
``q``. These are the K values appended to the cache for this
prefill step.
:param v:
New value tensor of shape ``[N, HKV, D]`` for the same tokens as
``q``.
:param k_cache:
Global key cache backing buffer of shape ``[CACHE_SIZE, D]``.
Keys for all cached tokens and heads are stored here; the mapping
from (batch, head, token index) to a row in this buffer is
given by ``global_page_table``.
:param v_cache:
Global value cache of shape ``[CACHE_SIZE, D]``. Must have the
same layout as ``k_cache`` (same ``CACHE_SIZE`` and ``D``).
:param seq_lens_bh:
Tensor of shape ``[B, HKV]`` (int32) giving, for each local batch
index and KV head, the number of cached tokens already present
in the paged KV cache before this prefill step.
:param global_page_table:
Tensor of shape ``[MAX_NUM_BATCHES, HKV, N_LOGICAL_PAGES_MAX]`` (int32)
mapping ``(true_batch_idx, kv_head, logical_page)`` to a physical
page id in the global KV cache. A physical page id `p` refers to
the slice:
``k_cache[p * PAGE_SIZE : (p + 1) * PAGE_SIZE]``.
:param batch_mapping:
Tensor of shape ``[B]`` (int16 / int32) mapping the local batch
index used in this kernel launch to the global batch index used
to index ``global_page_table``. This allows the same global cache
to be shared across multiple microbatches.
:param cu_seqlens_q:
Tensor of shape ``[B + 1]`` (int32) with cumulative sequence
lengths for the *new* tokens (q/k/v) in packed form. For batch
element ``b``:
``seqlen_q[b] = cu_seqlens_q[b + 1] - cu_seqlens_q[b]``.
The total number of tokens satisfies
``N = cu_seqlens_q[-1]``.
:param max_seqlen_q:
Maximum new query sequence length across the batch, i.e.
``max_b seqlen_q[b]``.
:param max_seqlen_k_cache:
Maximum cached sequence length across (batch, KV head), i.e.
``max_{b,h} seq_lens_bh[b, h]``.
:param HKV:
Number of KV heads. Must divide ``HQ``.
:param PAGE_SIZE:
Number of tokens stored per physical page in the paged KV cache.
``CACHE_SIZE`` must be divisible by ``PAGE_SIZE``.
:param sm_scale:
Optional scaling factor applied to the attention logits before
softmax. If ``None``, defaults to ``1.0 / sqrt(D)``.
:returns torch.Tensor:
Attention output of shape ``[N, HQ, D]``, with the same dtype and
device as ``q``. The output is laid out in the same packed
varlen format as the input queries, i.e. the first
``seqlen_q[0]`` rows correspond to batch 0, the next
``seqlen_q[1]`` rows to batch 1, etc.
"""
assert q.ndim == 3, "q should be [N, HQ, D]"
N, HQ, D = q.shape
assert (D & (D - 1)) == 0, "D must be power of two"
B = cu_seqlens_q.numel() - 1
assert B > 0
assert HQ % HKV == 0, "Number of query heads must divide number of keys heads"
H_g = HQ // HKV
# view Q as [HKV, N, QUERY_GROUP_SIZE, D]
out = torch.empty_like(q)
q = q.view(N, HKV, H_g, D).permute(1, 0, 2, 3)
out = out.view(N, HKV, H_g, D).permute(1, 0, 2, 3)
# K_app/V_app: [N, HKV, D] -> [HKV, N, D]
k_app = k.view(N, HKV, D).permute(1, 0, 2)
v_app = v.view(N, HKV, D).permute(1, 0, 2)
cu_seqlens_q = cu_seqlens_q.to(dtype=torch.int32, device=q.device)
seq_lens_bh = seq_lens_bh.to(dtype=torch.int32, device=q.device)
batch_mapping = batch_mapping.to(dtype=torch.int16, device=q.device)
N_LOGICAL_PAGES_MAX = global_page_table.shape[-1]
CACHE_SIZE = k_cache.shape[0]
assert v_cache.shape[0] == CACHE_SIZE
assert k_cache.shape[1] == D and v_cache.shape[1] == D
assert PAGE_SIZE > 0 and CACHE_SIZE % PAGE_SIZE == 0
if sm_scale is None:
sm_scale = 1.0 / math.sqrt(D)
# strides for Q [G, N, QUERY_GROUP_SIZE, D]
STRIDE_Q_G, STRIDE_Q_N, STRIDE_Q_H, STRIDE_Q_D = q.stride()
STRIDE_KC, STRIDE_VC = k_cache.stride(0), v_cache.stride(0)
# [G, N, D]
STRIDE_KA_G, STRIDE_KA_N, STRIDE_KA_D = k_app.stride()
STRIDE_VA_G, STRIDE_VA_N, STRIDE_VA_D = v_app.stride()
# OUT [G, N, QUERY_GROUP_SIZE, D]
STRIDE_OUT_G, STRIDE_OUT_N, STRIDE_OUT_H, STRIDE_OUT_D = out.stride()
# launch grid
maybe_set_allocator(
lambda size, align, _: torch.empty(size, dtype=torch.int8, device=q.device)
)
assert STRIDE_KA_D == STRIDE_VA_D == STRIDE_Q_D == STRIDE_OUT_D == 1, (
"final dimension must be contiguous"
)
def grid(META):
return HKV, B, triton.cdiv(max_seqlen_q, META["BLOCK_M"])
# On a fresh batch, max_seqlen_k_cache==0 (no KV prefix yet). Passing
# `triton.next_power_of_2(0)` into autotune constexpr keys breaks
# kernel selection / tuning and can yield garbage outputs.
_k_max_autotune = max(int(max_seqlen_k_cache), 1)
AUTOTUNE_MAX_Q_LEN = triton.next_power_of_2(max_seqlen_q)
AUTOTUNE_MAX_K_LEN = triton.next_power_of_2(_k_max_autotune)
_causal_head_sparse_varlen_with_cache[grid](
Q=q,
K_cache=k_cache,
V_cache=v_cache,
K_app=k_app,
V_app=v_app,
cu_seqlens_qk=cu_seqlens_q,
seq_lens_bh=seq_lens_bh,
page_table=global_page_table,
batch_mapping=batch_mapping,
OUT=out,
HKV=HKV,
QUERY_GROUP_SIZE=H_g,
PAGE_SIZE=PAGE_SIZE,
N_LOGICAL_PAGES_MAX=N_LOGICAL_PAGES_MAX,
STRIDE_Q_G=STRIDE_Q_G,
STRIDE_Q_N=STRIDE_Q_N,
STRIDE_Q_H=STRIDE_Q_H,
STRIDE_KC=STRIDE_KC,
STRIDE_VC=STRIDE_VC,
STRIDE_KA_G=STRIDE_KA_G,
STRIDE_KA_N=STRIDE_KA_N,
STRIDE_VA_G=STRIDE_VA_G,
STRIDE_VA_N=STRIDE_VA_N,
STRIDE_OUT_G=STRIDE_OUT_G,
STRIDE_OUT_N=STRIDE_OUT_N,
STRIDE_OUT_H=STRIDE_OUT_H,
sm_scale=sm_scale,
D=D,
AUTOTUNE_MAX_Q_LEN=AUTOTUNE_MAX_Q_LEN,
AUTOTUNE_MAX_K_LEN=AUTOTUNE_MAX_K_LEN,
)
return out.permute(1, 0, 2, 3).view(N, HQ, D) # already contiguous
autotune_configs_cc9 = [
triton.Config(
{"BLOCK_N": 64, "BLOCK_M": 64, "WARPSPEC": True}, num_warps=16, num_stages=3
),
triton.Config(
{"BLOCK_N": 64, "BLOCK_M": 64, "WARPSPEC": True}, num_warps=8, num_stages=3
),
triton.Config(
{"BLOCK_N": 64, "BLOCK_M": 32, "WARPSPEC": True}, num_warps=8, num_stages=4
),
triton.Config(
{"BLOCK_N": 64, "BLOCK_M": 32, "WARPSPEC": True}, num_warps=8, num_stages=3
),
triton.Config(
{"BLOCK_N": 64, "BLOCK_M": 32, "WARPSPEC": False}, num_warps=4, num_stages=3
),
triton.Config(
{"BLOCK_N": 64, "BLOCK_M": 16, "WARPSPEC": True}, num_warps=8, num_stages=3
),
triton.Config(
{"BLOCK_N": 64, "BLOCK_M": 16, "WARPSPEC": True}, num_warps=8, num_stages=4
),
triton.Config(
{"BLOCK_N": 64, "BLOCK_M": 16, "WARPSPEC": False}, num_warps=4, num_stages=4
),
triton.Config(
{"BLOCK_N": 32, "BLOCK_M": 32, "WARPSPEC": True}, num_warps=8, num_stages=4
),
triton.Config(
{"BLOCK_N": 32, "BLOCK_M": 32, "WARPSPEC": False}, num_warps=8, num_stages=4
),
triton.Config(
{"BLOCK_N": 32, "BLOCK_M": 16, "WARPSPEC": False}, num_warps=8, num_stages=3
),
triton.Config(
{"BLOCK_N": 32, "BLOCK_M": 16, "WARPSPEC": False}, num_warps=4, num_stages=4
),
]
autotune_configs_cc8 = [
triton.Config(
{"BLOCK_N": BN, "BLOCK_M": BM, "WARPSPEC": True}, num_warps=w, num_stages=s
)
for BN in [16, 32]
for BM in [64]
for w in [4, 8]
for s in [2, 3]
]
def prune_invalid_configs(configs, _, **kwargs):
return [
conf
for conf in configs
if not (conf.kwargs.get("BLOCK_N") == 32 and conf.kwargs.get("num_stages") == 4)
]
def get_autotune_configs():
if cuda_capability_geq(9, 0):
return autotune_configs_cc9
else:
return autotune_configs_cc8
@triton_autotune(
configs=get_autotune_configs(),
key=[
"HKV",
"QUERY_GROUP_SIZE",
"D",
"PAGE_SIZE",
"AUTOTUNE_MAX_K_LEN",
"AUTOTUNE_MAX_Q_LEN",
],
cache_results=True,
)
@triton.jit
def _causal_head_sparse_varlen_with_cache(
Q, # [HKV, N, QUERY_GROUP_SIZE, D] (non-contiguous)
K_cache,
V_cache, # [CACHE_SIZE, D]
K_app,
V_app, # [HKV, N, D]
cu_seqlens_qk, # [B+1]
seq_lens_bh, # [B, HKV]
page_table, # [B_total, HKV, N_LOGICAL_PAGES_MAX]
batch_mapping, # [B], maps local b -> global batch index
OUT, # [HKV, N, QUERY_GROUP_SIZE, D]
#
HKV: tl.constexpr,
QUERY_GROUP_SIZE: tl.constexpr,
PAGE_SIZE: tl.constexpr,
N_LOGICAL_PAGES_MAX,
STRIDE_Q_G,
STRIDE_Q_N,
STRIDE_Q_H,
STRIDE_KC,
STRIDE_VC,
STRIDE_KA_G,
STRIDE_KA_N,
STRIDE_VA_G,
STRIDE_VA_N,
STRIDE_OUT_G,
STRIDE_OUT_N,
STRIDE_OUT_H,
sm_scale,
#
D: tl.constexpr,
BLOCK_M: tl.constexpr,
BLOCK_N: tl.constexpr,
WARPSPEC: tl.constexpr,
AUTOTUNE_MAX_Q_LEN: tl.constexpr, # used for autotune key
AUTOTUNE_MAX_K_LEN: tl.constexpr, # used for autotune key
):
TOTAL_N_QUERIES: tl.constexpr = BLOCK_M * QUERY_GROUP_SIZE
pid_g = tl.program_id(0) # kv_head id in [0, HKV)
pid_b = tl.program_id(1) # batch id
pid_m = tl.program_id(2) # query-tile id within batch
# batch segment [qb, qe) in N
off_b = tl.load(cu_seqlens_qk + pid_b)
off_b1 = tl.load(cu_seqlens_qk + pid_b + 1)
seq_len_append = off_b1 - off_b
q_start = off_b + pid_m * BLOCK_M
q_end = tl.minimum(q_start + BLOCK_M, off_b1)
# number of queries in this tile for this batch
M = q_end - q_start
if M <= 0:
return
# cached length for (b, kv_head=pid_g)
L_cache = tl.load(seq_lens_bh + pid_b * HKV + pid_g)
# row indices flattened over [QUERY_GROUP_SIZE, M]
offs_row = tl.arange(0, TOTAL_N_QUERIES)
row_m = offs_row % BLOCK_M
row_h = offs_row // BLOCK_M
# valid rows: only those with row_m < M
row_mask = row_m < M
# global query index per row
q_idx = q_start + row_m
offs_d = tl.arange(0, D)
# Q tile: [TOTAL_N_QUERIES, D]
# Q layout: [HKV, N, QUERY_GROUP_SIZE, D]
q_ptrs = (
Q
+ pid_g * STRIDE_Q_G
+ q_idx[:, None] * STRIDE_Q_N
+ row_h[:, None] * STRIDE_Q_H
+ offs_d[None, :]
)
q = tl.load(q_ptrs, mask=row_mask[:, None], other=0.0)
e_max = tl.zeros([TOTAL_N_QUERIES], dtype=tl.float32) - float("inf")
e_sum = tl.zeros([TOTAL_N_QUERIES], dtype=tl.float32)
acc = tl.zeros([TOTAL_N_QUERIES, D], dtype=tl.float32)
offs_block_n = tl.arange(0, BLOCK_N)
qk_scale = sm_scale * 1.44269504
# 1) attend over cachee K/V
if L_cache > 0:
# map local (b) to global batch index
mapped_b = tl.load(batch_mapping + pid_b)
pt_base = (mapped_b * HKV + pid_g) * N_LOGICAL_PAGES_MAX
# iterate logical pages
num_lp = tl.cdiv(L_cache, PAGE_SIZE)
for lp in tl.range(0, num_lp):
# can overflow in 32 bits so upcast
phys = tl.load(page_table + pt_base + lp).to(tl.int64)
page_start = phys * PAGE_SIZE
# how many valid tokens in this page for this (b,g)
remain = L_cache - lp * PAGE_SIZE
page_len = tl.minimum(PAGE_SIZE, remain)
# iterate over this page in BLOCK_N chunks
for ks in tl.range(0, page_len, BLOCK_N):
offs_n = ks + offs_block_n
mask_n = offs_n < page_len
key_idx = page_start + offs_n
k_ptrs = K_cache + key_idx[:, None] * STRIDE_KC + offs_d[None, :]
k = tl.load(k_ptrs, mask=mask_n[:, None], other=0.0) # [BN, D]
qk = tl.dot(q, k.T) * qk_scale # [TOTAL_N_QUERIES, BN]
qk = tl.where(row_mask[:, None] & mask_n[None, :], qk, -1.0e6)
# softmax update
cur_max = tl.max(qk, 1)
n_e_max = tl.maximum(e_max, cur_max)
re_scale = tl.math.exp2(e_max - n_e_max)
p = tl.math.exp2(qk - n_e_max[:, None])
v_ptrs = V_cache + key_idx[:, None] * STRIDE_VC + offs_d[None, :]
v = tl.load(v_ptrs, mask=mask_n[:, None], other=0.0) # [BN, D]
acc = acc * re_scale[:, None]
acc = tl.dot(p.to(v.dtype), v, acc)
e_sum = e_sum * re_scale + tl.sum(p, 1)
e_max = n_e_max
# 2) attend over appended K_app/V_app (causal)
# appended tokens for batch b are in [off_b, off_b1)
# query tile is [q_start, q_end)
# for each query at index q_idx, valid appended keys k satisfy off_b <= k <= q_idx
if q_end > off_b:
# exactly one appended token
if seq_len_append == 1:
ka_ptrs = K_app + pid_g * STRIDE_KA_G + off_b * STRIDE_KA_N + offs_d
k = tl.load(ka_ptrs) # [D]
qk = tl.sum(q * k[None, :], 1) * qk_scale
qk = tl.where(row_mask, qk, -1.0e6)
n_e_max = tl.maximum(e_max, qk)
re_scale = tl.math.exp2(e_max - n_e_max)
p = tl.math.exp2(qk - n_e_max)
va_ptrs = V_app + pid_g * STRIDE_VA_G + off_b * STRIDE_VA_N + offs_d
v = tl.load(va_ptrs) # [D]
acc = acc * re_scale[:, None] + p[:, None] * v[None, :]
e_sum = e_sum * re_scale + p
else:
# off-band: k in [off_b, q_start)
# for all queries t in [q_start, q_end), any k < q_start satisfies k <= t.
# so no causal mask needed.
off_band_start = off_b
off_band_end = q_start
if off_band_end > off_band_start:
for ks in tl.range(off_band_start, off_band_end, BLOCK_N):
offs_n = ks + offs_block_n
mask_n = offs_n < off_band_end
ka_ptrs = (
K_app
+ pid_g * STRIDE_KA_G
+ offs_n[:, None] * STRIDE_KA_N
+ offs_d[None, :]
)
k = tl.load(ka_ptrs, mask=mask_n[:, None], other=0.0)
qk = tl.dot(q, k.T) * qk_scale
qk = tl.where(row_mask[:, None] & mask_n[None, :], qk, -1.0e6)
cur_max = tl.max(qk, 1)
n_e_max = tl.maximum(e_max, cur_max)
re_scale = tl.math.exp2(e_max - n_e_max)
p = tl.math.exp2(qk - n_e_max[:, None])
va_ptrs = (
V_app
+ pid_g * STRIDE_VA_G
+ offs_n[:, None] * STRIDE_VA_N
+ offs_d[None, :]
)
v = tl.load(va_ptrs, mask=mask_n[:, None], other=0.0)
acc = acc * re_scale[:, None]
acc = tl.dot(p.to(v.dtype), v, acc)
e_sum = e_sum * re_scale + tl.sum(p, 1)
e_max = n_e_max
# on-band remaining k
on_band_start = tl.maximum(q_start, off_b)
if on_band_start < q_end:
for ks in tl.range(on_band_start, q_end, BLOCK_N):
offs_n = ks + tl.arange(0, BLOCK_N)
mask_n = offs_n < q_end
ka_ptrs = (
K_app
+ pid_g * STRIDE_KA_G
+ offs_n[:, None] * STRIDE_KA_N
+ offs_d[None, :]
)
k = tl.load(ka_ptrs, mask=mask_n[:, None], other=0.0)
qk = tl.dot(q, k.T) * qk_scale
caus_mask = offs_n[None, :] <= q_idx[:, None]
full_mask = row_mask[:, None] & mask_n[None, :] & caus_mask
qk = tl.where(full_mask, qk, -1.0e6)
cur_max = tl.max(qk, 1)
n_e_max = tl.maximum(e_max, cur_max)
re_scale = tl.math.exp2(e_max - n_e_max)
p = tl.math.exp2(qk - n_e_max[:, None])
va_ptrs = (
V_app
+ pid_g * STRIDE_VA_G
+ offs_n[:, None] * STRIDE_VA_N
+ offs_d[None, :]
)
v = tl.load(va_ptrs, mask=mask_n[:, None], other=0.0)
acc = acc * re_scale[:, None]
acc = tl.dot(p.to(v.dtype), v, acc)
e_sum = e_sum * re_scale + tl.sum(p, 1)
e_max = n_e_max
# 3) write outputs
o = (acc / e_sum[:, None]).to(q.dtype)
out_ptrs = (
OUT
+ pid_g * STRIDE_OUT_G
+ q_idx[:, None] * STRIDE_OUT_N
+ row_h[:, None] * STRIDE_OUT_H
+ offs_d[None, :]
)
tl.store(out_ptrs, o, mask=row_mask[:, None])
from compactor_vllm.compression.common import (
BaseCompressionMethod,
NoCompression,
)
from compactor_vllm.compression.criticalkv import CriticalAdaKVCompression
from compactor_vllm.compression.compactor import CompactorCompression
from compactor_vllm.compression.compression_config import (
BatchCompressionParams,
CompressionMethod,
SequenceCompressionParams,
)
from compactor_vllm.compression.snapkv import SnapKVCompression
COMPRESSION_REGISTRY: dict[CompressionMethod, type[BaseCompressionMethod]] = {
CompressionMethod.CRITICALADAKV: CriticalAdaKVCompression,
CompressionMethod.COMPACTOR: CompactorCompression,
CompressionMethod.SNAPKV: SnapKVCompression,
CompressionMethod.NONE: NoCompression,
}
def apply_prerope_compression(q, k, v, context):
method = context.compression_context.compression_method
return COMPRESSION_REGISTRY[method].pre_rope_scoring(q, k, v, context=context)
def apply_postrope_compression(q, k, v, prerope_scores, context):
method = context.compression_context.compression_method
return COMPRESSION_REGISTRY[method].post_rope_scoring(
q, k, v, prerope_scores, context=context
)
__all__ = [
"apply_prerope_compression",
"apply_postrope_compression",
"CompressionMethod",
"BatchCompressionParams",
"SequenceCompressionParams",
"COMPRESSION_REGISTRY"
]
from abc import ABC, abstractmethod
from typing import Optional
import torch
from compactor_vllm.kv_cache.store_kv_cache import prefill_store_topk_kv
class BaseCompressionMethod(ABC):
"""
Abstract interface for KV cache compression methods.
A compression method is implemented as a pair of optional scoring phases
that run before and after rotary position embedding (RoPE) is applied:
1. ``pre_rope_scoring`` operates on pre-RoPE Q/K.
2. ``post_rope_scoring`` operates on post-RoPE Q/K and can either:
- refine / reweight the pre-RoPE scores, or
- compute potentially position-aware.
Concrete subclasses are expected to implement both
static methods and return a single tensor of scores (or ``None`` if the
phase is a no-op), which the caller can then feed into the shared
“scores → top-k indices → KV extraction” pipeline.
"""
@staticmethod
@abstractmethod
def pre_rope_scoring(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
context,
) -> Optional[torch.Tensor]:
"""
Compute per-token importance scores from pre-RoPE queries/keys.
Args:
:param q:
Pre-RoPE query tensor. Shape ``[total_tokens, HQ, D]```.
:param k:
Pre-RoPE key tensor. Shape ``[total_tokens, HKV, D]```.
:param v:
Value tensor. Shape ``[total_tokens, HKV, D]```
:param context:
compactor_vllm.utils.context.Context object carrying additional metadata,
such as batch mappings or temporary buffers
Returns:
:return Optional[torch.Tensor]:
A tensor of scores (e.g. per-token, per-head importance values)
to be passed to ``post_rope_scoring`` or directly into the
top-k selection step. If this phase is a no-op, implementations
should return ``None``. Shape ``[total_tokens, HKV]```.
"""
pass
@staticmethod
@abstractmethod
def post_rope_scoring(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
pre_rope_scores: Optional[torch.Tensor],
context,
) -> Optional[torch.Tensor]:
"""
Compute or refine importance scores from post-RoPE queries/keys.
This method is called after rotary embeddings have been applied. It can
optionally use both the post-RoPE Q/K and any scores produced by
``pre_rope_scoring`` to produce final scores used for token selection.
Common patterns include:
* Using ``pre_rope_scores`` as a base signal and applying a
position-aware correction.
* Only computing scores that depend on absolute or relative positions.
* Simply passing through ``pre_rope_scores`` unchanged.
Args:
:param q:
Post-RoPE query tensor. Shape ``[total_tokens, HQ, D]```.
:param k:
Post-RoPE key tensor. Shape ``[total_tokens, HKV, D]```.
:param pre_rope_scores:
Optional scores returned by ``pre_rope_scoring``. May be
``None`` if the pre-RoPE phase returned None.
:param v:
Value tensor. Shape ``[total_tokens, HKV, D]```
:param context:
compactor_vllm.utils.context.Context object carrying additional metadata,
such as batch mappings or temporary buffers
Returns:
:return Optional[torch.Tensor]:
Final importance scores to be consumed by the compression
pipeline (for top-k token selection). If this phase is a
no-op, implementations may return ``pre_rope_scores``. If
None is returned, no compression will be applied.
"""
pass
class NoCompression(BaseCompressionMethod):
"""
Trivial compression method that disables KV cache compression.
"""
@staticmethod
def pre_rope_scoring(
q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, context
) -> Optional[torch.Tensor]:
return None
@staticmethod
def post_rope_scoring(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
pre_rope_scores: torch.Tensor,
context,
) -> Optional[torch.Tensor]:
return pre_rope_scores
def extract_and_store_top_kv(
scores: torch.Tensor,
cu_seqlens_k: torch.Tensor,
max_k_len: int,
top_k: int,
H: int,
new_keys: torch.Tensor, # [N_total, H, D]
new_vals: torch.Tensor, # [N_total, H, D]
num_tokens_to_retain: torch.Tensor, # [B] int32
page_table: torch.Tensor, # [B_total, H, N_LOGICAL_PAGES_MAX] int32
batch_mapping: torch.Tensor, # [B] int32 (local -> true batch rows)
bh_lens: torch.Tensor, # [B, H] int32 (contiguous), UPDATED atomically
k_cache: torch.Tensor, # [N_PAGES * PAGE_SIZE, D]
v_cache: torch.Tensor, # [N_PAGES * PAGE_SIZE, D]
PAGE_SIZE: int,
PAD_TO_PAGE_SIZE: bool = True,
K_TILE: int = 16,
padding: float = -float("inf"),
):
"""helper method to extract and store top-k indices into KV cache (so they can be executed in a single stream)"""
indices_topk = scores_to_retain_indices(
scores,
cu_seqlens_k=cu_seqlens_k,
max_k_len=max_k_len,
top_k=top_k,
H=H,
padding=padding,
)
prefill_store_topk_kv(
new_keys=new_keys,
new_vals=new_vals,
indices_topk=indices_topk,
num_tokens_to_retain=num_tokens_to_retain,
page_table=page_table,
batch_mapping=batch_mapping,
bh_lens=bh_lens,
k_cache=k_cache,
v_cache=v_cache,
cu_seqlens_k=cu_seqlens_k,
PAGE_SIZE=PAGE_SIZE,
PAD_TO_PAGE_SIZE=PAD_TO_PAGE_SIZE,
K_TILE=K_TILE,
)
def scores_to_retain_indices(
scores: torch.Tensor,
cu_seqlens_k: torch.Tensor,
max_k_len: int,
top_k: int,
H: int,
padding: float = -float("inf"),
) -> torch.Tensor:
"""
Select global top-k token–head indices per sequence from packed scores.
This helper takes per-token, per-head scores in packed varlen form and
returns, for each batch element, the indices of the top-k (token, head)
pairs in the flattened global layout.
Inputs are assumed to follow the usual packed varlen convention:
• ``scores`` is laid out as ``[N_total, H]``, where:
``N_total = sum_b seqlen_k[b]``
and ``HKV`` is the number of KV heads.
• ``cu_seqlens_k`` is ``[B + 1]`` (int32), giving cumulative lengths
for the keys per batch:
``seqlen_k[b] = cu_seqlens_k[b + 1] - cu_seqlens_k[b]``.
• ``max_k_len`` is an upper bound on ``seqlen_k[b]`` across the batch.
The function pads each sequence to length ``max_k_len`` with ``padding``
(default: ``-inf``), flattens the per-sequence scores into shape
``[B, max_k_len * H]``, and runs a per-batch top-k. The returned indices
are shifted so that they directly index into the flattened global
score layout of shape ``[N_total * H]``:
global_index = (token_global_offset * H) + head_index
Args:
:param scores:
Tensor of shape ``[N_total, HKV]`` containing scores for each
(token, head) pair in packed varlen format.
:param cu_seqlens_k:
Tensor of shape ``[B + 1]`` (int32) with cumulative key sequence
lengths for each batch element. The total number of tokens
satisfies ``N_total = cu_seqlens_k[-1]``.
:param max_k_len:
Maximum key sequence length across the batch (i.e.
``max_b seqlen_k[b]``). Used to allocate the padded buffer.
:param top_k:
Number of (token, head) entries to retain **per batch element**.
If ``top_k > max_k_len * HKV``, it is clamped to ``max_k_len * HKV``.
:param H:
Number of key heads; must match ``scores.shape[1]``.
:param padding:
Padding value used when extending sequences shorter than
``max_k_len``. Defaults to ``-inf``, so that padded positions are
never selected in the top-k.
Returns:
:return torch.Tensor:
Tensor of shape ``[B, k_eff]`` (int64) where
``k_eff = min(top_k, max_k_len * H)``. Each entry is a global
index into the flattened score array of shape ``[N_total * H]``
(i.e. scores viewed as ``scores.view(-1)``),
"""
# idea: pad and then select top-k.
B, device = cu_seqlens_k.numel() - 1, scores.device
padded = torch.full(
(B, max_k_len, H), fill_value=padding, dtype=scores.dtype, device=device
)
for b in range(B):
s, e = int(cu_seqlens_k[b]), int(cu_seqlens_k[b + 1])
padded[b, : e - s, :].copy_(scores[s:e, :])
flat = padded.view(B, max_k_len * H)
idx = torch.topk(
flat, k=min(top_k, max_k_len * H), dim=1, largest=True, sorted=True
).indices
return idx + (cu_seqlens_k[:-1] * H).unsqueeze(-1)
"""
Compactor 压缩:与 kvpress ``CompactorPress`` / ``LeverageScorePress`` / ``NonCausalAttnPress``
算法对齐(Cholesky 杠杆分、右高斯 sketch、非因果分块注意力无 1/sqrt(d) 缩放、×||V||、avg_pool、
全局 z-score、blending 与首尾 sink pad)。
非因果分块注意力与 ``×||V||``+``avg_pool1d(k=3)`` 在 CUDA 上为 Triton;非 CUDA 回退 PyTorch。
"""
from __future__ import annotations
import math
from typing import List, Optional
import torch
import triton
import triton.language as tl
from transformers.models.llama.modeling_llama import repeat_kv
from compactor_vllm.compression.common import BaseCompressionMethod
from compactor_vllm.utils.helpers import maybe_execute_in_stream
def resolve_kvpress_compactor_blending(compression_context) -> float:
"""与 kvpress ``CompactorPress.score`` 相同:``blending`` 或 ``compression_ratio``,再否则 0.35。"""
if compression_context is None:
return 0.35
b = getattr(compression_context, "compactor_blending", None)
if b is not None:
return float(b)
cr = getattr(compression_context, "compression_ratio", None)
if cr is not None:
return float(cr)
return 0.35
class CompactorCompression(BaseCompressionMethod):
"""与 kvpress ``CompactorPress`` / ``NonCausalAttnPress`` 默认 ``chunk_size=256`` 一致。"""
chunk_size: int = 256
@staticmethod
def pre_rope_scoring(
q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, context
) -> Optional[torch.Tensor]:
compression_context = context.compression_context
return maybe_execute_in_stream(
kvpress_leverage_scores_packed,
k,
context.cu_seqlens_q,
compression_context,
STORE_STREAM=context.STORE_STREAM,
)
@staticmethod
def post_rope_scoring(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
pre_rope_scores: torch.Tensor,
context,
) -> Optional[torch.Tensor]:
compression_context = context.compression_context
blending = resolve_kvpress_compactor_blending(compression_context)
return maybe_execute_in_stream(
kvpress_compactor_post_rope,
q,
k,
v,
context.cu_seqlens_q,
pre_rope_scores,
compression_context,
context.max_seqlen_q,
chunk_size=CompactorCompression.chunk_size,
blending=float(blending),
STORE_STREAM=context.STORE_STREAM,
)
# ---------------------------------------------------------------------------
# Cholesky 杠杆分(kvpress ``LeverageScorePress``)
# ---------------------------------------------------------------------------
def chol_with_jitter(
G: torch.Tensor, jitter: float = 0.0, max_tries: int = 5
) -> torch.Tensor:
identity = torch.eye(G.shape[-1], device=G.device, dtype=G.dtype)
cur = float(jitter)
for _ in range(max_tries):
L, info = torch.linalg.cholesky_ex(G + cur * identity, upper=False)
if bool((info == 0).all()):
return L
cur = max(1e-8, (1e-2 if cur == 0.0 else 10.0 * cur))
raise RuntimeError(f"Cholesky failed after {max_tries} tries.")
def compute_leverage_scores_mid(
key_states: torch.Tensor, sketch_dimension: int
) -> torch.Tensor:
"""
与 kvpress ``LeverageScorePress.compute_leverage_scores`` 相同;输入 ``[L, H, D]``,
返回 ``[L, H]``(未 z-score)。
维序与 kvpress 的 ``(B, H, S, D)`` 对齐:先变为 ``[1, H, L, D]``,在序列维(``dim=-2``)
上中心化,再与 ``Phi`` 为 ``(1, H, D, K)`` 的 batch 矩阵乘得到 ``[1, H, L, K]``。
"""
d, k = key_states.shape[-1], sketch_dimension
device, dtype = key_states.device, key_states.dtype
H = key_states.shape[1]
Phi = torch.randn(1, H, d, k, device=device, dtype=dtype) * (1.0 / math.sqrt(k))
# [L, H, d] -> [1, H, L, d],与 kvpress (B,H,S,d) 一致
X0 = key_states.transpose(0, 1).unsqueeze(0).contiguous()
X = X0 - X0.mean(dim=-2, keepdim=True)
X = torch.matmul(X, Phi).to(torch.float32)
XT = X.transpose(-2, -1)
G = XT @ X
L = chol_with_jitter(
0.5 * (G + G.transpose(-2, -1)), jitter=1e-2, max_tries=5
)
inv_Xt = torch.cholesky_solve(XT, L, upper=False)
scores = (X * inv_Xt.transpose(-2, -1)).sum(dim=-1).clamp_min(0)
# [1, H, L] -> [L, H]
return scores.squeeze(0).transpose(0, 1).contiguous()
def kvpress_leverage_scores_packed(
key_states: torch.Tensor,
cu_seqlens: torch.Tensor,
compression_ctx,
) -> torch.Tensor:
device = key_states.device
N, Hkv, _D = key_states.shape
sketch_dim = int(getattr(compression_ctx, "sketch_dimension", 48))
sink_start = int(getattr(compression_ctx, "sink_size_start", 8))
sink_end = int(getattr(compression_ctx, "sink_size_end", 4))
out = torch.zeros(N, Hkv, device=device, dtype=torch.float32)
mids_flat: list[torch.Tensor] = []
mid_ranges: list[tuple[int, int, int]] = []
for b in range(cu_seqlens.numel() - 1):
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
L = k_end - k_beg
if L == 0:
continue
left_keep = min(sink_start, L)
right_keep = min(sink_end, max(0, L - left_keep))
mid_start = k_beg + left_keep
mid_end = k_end - right_keep
if mid_start >= mid_end:
continue
k_mid = key_states[mid_start:mid_end, :, :].contiguous()
raw = compute_leverage_scores_mid(k_mid, sketch_dim)
mids_flat.append(raw.reshape(-1))
mid_ranges.append((mid_start, mid_end, Hkv))
if not mids_flat:
return out
flat = torch.cat(mids_flat, dim=0)
z = _zscore_flat_f32_global(flat)
offset = 0
for (mid_start, mid_end, _Hkv), r in zip(mid_ranges, mids_flat):
n = r.numel()
seg = z[offset : offset + n].view(mid_end - mid_start, Hkv)
out[mid_start:mid_end, :] = seg
offset += n
return out
# ---------------------------------------------------------------------------
# 非因果分块注意力(kvpress ``NonCausalAttnPress.non_causal_chunked_attn``)— Triton
# ---------------------------------------------------------------------------
def _non_causal_chunked_attn_pytorch(
q: torch.Tensor, k: torch.Tensor, chunk_size: int
) -> torch.Tensor:
"""参考实现:与 kvpress 逐算子一致。"""
assert chunk_size > 0 and q.shape == k.shape
L, H, d = q.shape
B = 1
q = q.permute(1, 0, 2).unsqueeze(0).contiguous()
k = k.permute(1, 0, 2).unsqueeze(0).contiguous()
_B, H, S, _d = k.shape
S_pad = math.ceil(S / chunk_size) * chunk_size
pad_len = S_pad - S
if pad_len > 0:
q_padded = torch.cat(
[q, torch.zeros(B, H, pad_len, d, device=q.device, dtype=q.dtype)], dim=2
)
k_padded = torch.cat(
[k, torch.zeros(B, H, pad_len, d, device=k.device, dtype=k.dtype)], dim=2
)
last_chunk_start = (S // chunk_size) * chunk_size
in_valid = torch.arange(last_chunk_start, S_pad, device=q.device) >= S
query_mask = key_mask = in_valid.view(1, 1, chunk_size).expand(B, H, chunk_size)
else:
q_padded, k_padded = q, k
last_chunk_start = ((S - 1) // chunk_size) * chunk_size
in_valid = torch.arange(last_chunk_start, S_pad, device=q.device) >= S
query_mask = key_mask = in_valid.view(1, 1, chunk_size).expand(B, H, chunk_size)
num_chunks = S_pad // chunk_size
q_chunks = q_padded.view(B, H, num_chunks, chunk_size, d)
k_chunks = k_padded.view(B, H, num_chunks, chunk_size, d)
dots = torch.matmul(q_chunks, k_chunks.transpose(-2, -1))
dots[:, :, -1].masked_fill_(query_mask.unsqueeze(-1), 0)
dots[:, :, -1].masked_fill_(key_mask.unsqueeze(-2), -1e-9)
attn = torch.softmax(dots.to(torch.float32), dim=-1)
out = attn.sum(dim=-2).view(B, H, S_pad)[..., :S]
return out.squeeze(0).transpose(0, 1).contiguous()
@triton.jit
def _non_causal_chunk_row_kernel(
Q_ptr,
K_ptr,
Out_ptr,
stride_qh,
stride_qs,
stride_qd,
stride_kh,
stride_ks,
stride_kd,
stride_oh,
stride_os,
S,
S_pad,
num_chunks,
CHUNK_SIZE: tl.constexpr,
D: tl.constexpr,
BLOCK_D: tl.constexpr,
ND: tl.constexpr,
):
"""
每个 program:一个 head、一个 chunk、一条 query 行。
对 logits 行做 softmax(dim=-1),再对 key 列 j 做 atomic_add 累加到输出(与 sum over query 等价)。
"""
h = tl.program_id(0)
c = tl.program_id(1)
iq = tl.program_id(2)
g_i = c * CHUNK_SIZE + iq
offs_j = tl.arange(0, CHUNK_SIZE)
logits = tl.zeros([CHUNK_SIZE], dtype=tl.float32)
for db in range(ND):
offs_d = tl.arange(0, BLOCK_D) + db * BLOCK_D
mask_d = offs_d < D
q_off = (
h * stride_qh + g_i * stride_qs + offs_d * stride_qd
)
qd = tl.load(Q_ptr + q_off, mask=mask_d, other=0.0).to(tl.float32)
g_j = c * CHUNK_SIZE + offs_j
k_row_off = h * stride_kh + g_j[:, None] * stride_ks + offs_d[None, :] * stride_kd
kj = tl.load(K_ptr + k_row_off, mask=mask_d[None, :], other=0.0).to(tl.float32)
logits += tl.sum(qd[None, :] * kj, axis=1)
row_invalid = g_i >= S
g_j_all = c * CHUNK_SIZE + offs_j
col_invalid = g_j_all >= S
logits = tl.where(row_invalid, tl.zeros([CHUNK_SIZE], dtype=tl.float32), logits)
logits = tl.where(
row_invalid,
logits,
tl.where(col_invalid, tl.full([CHUNK_SIZE], -1e-9, dtype=tl.float32), logits),
)
m = tl.max(logits)
logits = logits - m
exp_v = tl.exp(logits)
denom = tl.sum(exp_v)
p = exp_v / denom
out_base = h * stride_oh + g_j_all * stride_os
tl.atomic_add(Out_ptr + out_base, p, mask=g_j_all < S)
def _non_causal_chunked_attn_triton(
q: torch.Tensor, k: torch.Tensor, chunk_size: int
) -> torch.Tensor:
"""CUDA Triton:与 ``_non_causal_chunked_attn_pytorch`` 同算法。"""
assert q.is_cuda and k.is_cuda and q.shape == k.shape
L, H, d = q.shape
assert chunk_size > 0
S_pad = math.ceil(L / chunk_size) * chunk_size
pad_len = S_pad - L
if pad_len > 0:
zq = torch.zeros(
pad_len, H, d, device=q.device, dtype=q.dtype, requires_grad=False
)
zk = torch.zeros(
pad_len, H, d, device=k.device, dtype=k.dtype, requires_grad=False
)
q = torch.cat([q, zq], dim=0)
k = torch.cat([k, zk], dim=0)
Q = q.transpose(0, 1).contiguous().to(dtype=torch.float32)
K = k.transpose(0, 1).contiguous().to(dtype=torch.float32)
num_chunks = S_pad // chunk_size
out_acc = torch.zeros(H, S_pad, device=q.device, dtype=torch.float32)
S = int(L)
grid = (H, num_chunks, chunk_size)
BLOCK_D = 32 if d <= 128 else 64
ND = (d + BLOCK_D - 1) // BLOCK_D
_non_causal_chunk_row_kernel[grid](
Q,
K,
out_acc,
Q.stride(0),
Q.stride(1),
Q.stride(2),
K.stride(0),
K.stride(1),
K.stride(2),
out_acc.stride(0),
out_acc.stride(1),
S,
S_pad,
int(num_chunks),
CHUNK_SIZE=chunk_size,
D=d,
BLOCK_D=BLOCK_D,
ND=ND,
num_warps=4,
)
return out_acc[:, :S].transpose(0, 1).contiguous()
def non_causal_chunked_attn(q: torch.Tensor, k: torch.Tensor, chunk_size: int) -> torch.Tensor:
"""q, k: ``[L, H, d]`` → ``[L, H]``;**无** ``1/sqrt(d)``。CUDA 用 Triton,否则 PyTorch。"""
if q.is_cuda and k.is_cuda:
return _non_causal_chunked_attn_triton(q, k, chunk_size)
return _non_causal_chunked_attn_pytorch(q, k, chunk_size)
# ---------------------------------------------------------------------------
# ×||V|| + avg_pool1d(k=3) — Triton(CUDA)
# ---------------------------------------------------------------------------
@triton.jit
def _mul_vnorm_avgpool3_kernel(
A_ptr,
V_ptr,
OUT_ptr,
stride_al,
stride_ah,
stride_vl,
stride_vh,
stride_vd,
stride_ol,
stride_oh,
L,
D: tl.constexpr,
):
"""Triton 不支持嵌套 def;``t_at`` 逻辑对 ``l-1,l,l+1`` 各展开一份。"""
l = tl.program_id(0)
h = tl.program_id(1)
offs = tl.arange(0, D)
pos_m1 = l - 1
inb_m1 = (pos_m1 >= 0) & (pos_m1 < L)
ps_m1 = tl.where(inb_m1, pos_m1, 0)
a_m1 = tl.load(
A_ptr + ps_m1 * stride_al + h * stride_ah,
mask=inb_m1,
other=0.0,
).to(tl.float32)
v_m1 = tl.load(
V_ptr + ps_m1 * stride_vl + h * stride_vh + offs * stride_vd,
mask=inb_m1,
other=0.0,
).to(tl.float32)
s_m1 = tl.where(inb_m1, a_m1 * tl.sqrt(tl.sum(v_m1 * v_m1)), 0.0)
inb_0 = (l >= 0) & (l < L)
ps0 = tl.where(inb_0, l, 0)
a0 = tl.load(
A_ptr + ps0 * stride_al + h * stride_ah,
mask=inb_0,
other=0.0,
).to(tl.float32)
v0 = tl.load(
V_ptr + ps0 * stride_vl + h * stride_vh + offs * stride_vd,
mask=inb_0,
other=0.0,
).to(tl.float32)
s_0 = tl.where(inb_0, a0 * tl.sqrt(tl.sum(v0 * v0)), 0.0)
pos_p1 = l + 1
inb_p1 = (pos_p1 >= 0) & (pos_p1 < L)
ps_p1 = tl.where(inb_p1, pos_p1, 0)
a_p1 = tl.load(
A_ptr + ps_p1 * stride_al + h * stride_ah,
mask=inb_p1,
other=0.0,
).to(tl.float32)
v_p1 = tl.load(
V_ptr + ps_p1 * stride_vl + h * stride_vh + offs * stride_vd,
mask=inb_p1,
other=0.0,
).to(tl.float32)
s_p1 = tl.where(inb_p1, a_p1 * tl.sqrt(tl.sum(v_p1 * v_p1)), 0.0)
out = (s_m1 + s_0 + s_p1) * (1.0 / 3.0)
tl.store(OUT_ptr + l * stride_ol + h * stride_oh, out)
def _mul_vnorm_avgpool3_fused(
a: torch.Tensor, v: torch.Tensor, out: torch.Tensor | None = None
) -> torch.Tensor:
assert a.dim() == 2 and v.dim() == 3 and a.shape[0] == v.shape[0] and a.shape[1] == v.shape[1]
L, H, D = v.shape
a = a.contiguous()
v = v.contiguous()
if a.dtype != torch.float32:
a = a.float()
if out is None:
out = torch.empty((L, H), device=v.device, dtype=torch.float32)
if L == 0 or H == 0:
return out
grid = (L, H)
_mul_vnorm_avgpool3_kernel[grid](
a,
v,
out,
a.stride(0),
a.stride(1),
v.stride(0),
v.stride(1),
v.stride(2),
out.stride(0),
out.stride(1),
L,
D=D,
num_warps=4,
)
return out
def _maybe_mul_vnorm_avgpool3_fused(a: torch.Tensor, v: torch.Tensor) -> torch.Tensor:
if not a.is_cuda or not v.is_cuda:
import torch.nn.functional as F
s = a * v.norm(dim=-1)
return (
F.avg_pool1d(s.transpose(0, 1).unsqueeze(0), kernel_size=3, padding=1, stride=1)
.squeeze(0)
.transpose(0, 1)
)
return _mul_vnorm_avgpool3_fused(a, v)
@triton.jit
def _zscore_elem_1d_kernel(
X_ptr,
OUT_ptr,
n,
mean,
inv_std,
BLOCK: tl.constexpr,
):
pid = tl.program_id(0)
offs = pid * BLOCK + tl.arange(0, BLOCK)
mask = offs < n
x = tl.load(X_ptr + offs, mask=mask, other=0.0)
tl.store(OUT_ptr + offs, (x - mean) * inv_std, mask=mask)
def _zscore_flat_f32_global(x: torch.Tensor) -> torch.Tensor:
"""
与 kvpress ``(t - t.mean()) / t.std()`` 一致的一维全局 z-score。
``mean/std`` 用 PyTorch;CUDA 上缩放阶段用 Triton 逐元素写入。
"""
if x.numel() == 0:
return x
mu = x.mean()
sig = x.std().clamp_min(1e-6)
inv = 1.0 / sig
if not x.is_cuda:
return (x - mu) * inv
x = x.contiguous()
out = torch.empty_like(x)
n = x.numel()
BLOCK = 1024
grid = (triton.cdiv(n, BLOCK),)
_zscore_elem_1d_kernel[grid](
x,
out,
n,
float(mu.item()),
float(inv.item()),
BLOCK=BLOCK,
num_warps=4,
)
return out
def _attn_scores_kvpress_middle(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
cu_seqlens: torch.Tensor,
sink_start: int,
sink_end: int,
chunk_size: int,
do_zscore: bool = True,
) -> torch.Tensor:
"""仅中间子序列上的非因果分 + ×||V|| + avg_pool;输出全长 ``[N, Hkv]``,非中间为 0。"""
N, HQ, D = q.shape
Hkv = k.shape[1]
G = HQ // Hkv
device = q.device
attn_out = torch.zeros(N, Hkv, device=device, dtype=torch.float32)
parts: list[torch.Tensor] = []
for b in range(cu_seqlens.numel() - 1):
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
L = k_end - k_beg
if L == 0:
continue
left_keep = min(sink_start, L)
right_keep = min(sink_end, max(0, L - left_keep))
mid_start = k_beg + left_keep
mid_end = k_end - right_keep
if mid_start >= mid_end:
continue
q_m = q[mid_start:mid_end, :, :].contiguous()
k_m = k[mid_start:mid_end, :, :].contiguous()
v_m = v[mid_start:mid_end, :, :].contiguous()
# HF ``repeat_kv`` 约定:``[batch, num_kv_heads, seq_len, head_dim]``
k_4d = k_m.unsqueeze(0).transpose(1, 2).contiguous() # [1, Hkv, Lm, D]
k_rep = repeat_kv(k_4d, G)[0].transpose(0, 1).contiguous() # [Lm, HQ, D]
A = non_causal_chunked_attn(q_m, k_rep, chunk_size)
Lm, HQa = A.shape
assert HQa == HQ
A = A.view(Lm, Hkv, G).mean(dim=-1)
scores = _maybe_mul_vnorm_avgpool3_fused(A, v_m)
parts.append(scores.reshape(-1))
if not parts:
return attn_out
flat_a = torch.cat(parts, dim=0)
if do_zscore:
z_a = _zscore_flat_f32_global(flat_a)
else:
z_a = flat_a
offset = 0
for b in range(cu_seqlens.numel() - 1):
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
L = k_end - k_beg
if L == 0:
continue
left_keep = min(sink_start, L)
right_keep = min(sink_end, max(0, L - left_keep))
mid_start = k_beg + left_keep
mid_end = k_end - right_keep
if mid_start >= mid_end:
continue
n = (mid_end - mid_start) * Hkv
attn_out[mid_start:mid_end, :] = z_a[offset : offset + n].view(
mid_end - mid_start, Hkv
)
offset += n
return attn_out
def non_causal_attn_scores(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
cu_seqlens_qk: torch.Tensor,
max_seqlen_qk: int,
chunk_size: int,
sm_scale: float = None,
normalize: bool = True,
context_lens: Optional[List[int]] = None,
protected_first_tokens: Optional[List[int]] = None,
protected_last_tokens: Optional[List[int]] = None,
*,
accum_scores: torch.Tensor = None,
accum_blending: float = None,
) -> torch.Tensor:
"""
与 kvpress 非因果分支一致(**忽略** ``sm_scale``:点积不乘 ``1/sqrt(d)``)。
``normalize=True``:对中间子序列拼接后做全局 z-score(与单独非因果 press 一致)。
然后 ``out += accum_blending * accum_scores``(若给定);最后可对首尾 protected 置 ``inf``。
"""
del sm_scale, max_seqlen_qk
sink_start, sink_end = 8, 4
out = _attn_scores_kvpress_middle(
q,
k,
v,
cu_seqlens_qk,
sink_start,
sink_end,
chunk_size,
do_zscore=normalize,
)
if accum_scores is not None:
w = 0.5 if accum_blending is None else float(accum_blending)
out = out + w * accum_scores.to(device=out.device, dtype=out.dtype)
if protected_first_tokens is not None and protected_last_tokens is not None and context_lens:
start = 0
for first, last, Lc in zip(
protected_first_tokens, protected_last_tokens, context_lens
):
out[start : start + int(first)].fill_(torch.inf)
out[start + int(Lc) - int(last) : start + int(Lc)].fill_(torch.inf)
start += int(Lc)
return out
def kvpress_compactor_post_rope(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
cu_seqlens: torch.Tensor,
pre_rope_scores: torch.Tensor,
compression_ctx,
max_seqlen_q: int,
chunk_size: int,
blending: float,
) -> torch.Tensor:
del max_seqlen_q
Hkv = k.shape[1]
device = q.device
sink_start = int(getattr(compression_ctx, "sink_size_start", 8))
sink_end = int(getattr(compression_ctx, "sink_size_end", 4))
context_lens: Optional[List[int]] = getattr(
compression_ctx, "context_lens", None
)
protected_first: Optional[List[int]] = getattr(
compression_ctx, "protected_first_tokens", None
)
protected_last: Optional[List[int]] = getattr(
compression_ctx, "protected_last_tokens", None
)
attn_out = _attn_scores_kvpress_middle(
q, k, v, cu_seqlens, sink_start, sink_end, chunk_size
)
lev = pre_rope_scores.to(device=device, dtype=torch.float32)
blended = torch.zeros_like(lev)
for b in range(cu_seqlens.numel() - 1):
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
L = k_end - k_beg
if L == 0:
continue
left_keep = min(sink_start, L)
right_keep = min(sink_end, max(0, L - left_keep))
mid_start = k_beg + left_keep
mid_end = k_end - right_keep
if mid_start >= mid_end:
continue
blended[mid_start:mid_end, :] = (
blending * lev[mid_start:mid_end, :] + attn_out[mid_start:mid_end, :]
)
pad_val = blended.max()
if not torch.isfinite(pad_val) or pad_val == 0:
pad_val = torch.tensor(1.0, device=device, dtype=torch.float32)
for b in range(cu_seqlens.numel() - 1):
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
L = k_end - k_beg
if L == 0:
continue
left_keep = min(sink_start, L)
right_keep = min(sink_end, max(0, L - left_keep))
mid_start = k_beg + left_keep
mid_end = k_end - right_keep
if left_keep > 0:
blended[k_beg:mid_start, :] = pad_val
if right_keep > 0:
blended[mid_end:k_end, :] = pad_val
if protected_first is not None and protected_last is not None and context_lens:
start = 0
for first, last, Lc in zip(
protected_first, protected_last, context_lens
):
blended[start : start + int(first)].fill_(torch.inf)
blended[start + int(Lc) - int(last) : start + int(Lc)].fill_(torch.inf)
start += int(Lc)
return blended
import logging
import math
from typing import List, Optional
import torch
import triton
from tqdm.contrib.logging import logging_redirect_tqdm
from triton import language as tl
from compactor_vllm.compression.common import BaseCompressionMethod
from compactor_vllm.utils.helpers import maybe_execute_in_stream
from compactor_vllm.utils.triton_compat import autotune as triton_autotune
logger = logging.getLogger(__name__)
class CompactorCompression(BaseCompressionMethod):
chunk_size: int = 128
@staticmethod
def pre_rope_scoring(
q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, context
) -> Optional[torch.Tensor]:
compression_context = context.compression_context
scores = maybe_execute_in_stream(
approximate_leverage_scores,
k,
compression_context.context_lens,
compression_context.PHI,
normalize=True,
chunk_size=compression_context.compression_chunk_size,
STORE_STREAM=context.STORE_STREAM,
)
return scores
@staticmethod
def post_rope_scoring(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
pre_rope_scores: torch.Tensor,
context,
) -> Optional[torch.Tensor]:
compression_context = context.compression_context
return maybe_execute_in_stream(
non_causal_attn_scores,
q,
k,
v,
context.cu_seqlens_q,
context.max_seqlen_q,
chunk_size=CompactorCompression.chunk_size,
sm_scale=1.0,
normalize=True,
accum_scores=pre_rope_scores,
context_lens=compression_context.context_lens,
protected_first_tokens=compression_context.protected_first_tokens,
protected_last_tokens=compression_context.protected_last_tokens,
accum_blending=0.5,
)
def split_into_chunks(xs, chunk_size):
"""
Convert a list of sequence lengths into a sequence of coalesced chunk lengths.
Given an iterable of per-sequence context lengths ``xs`` and a target ``chunk_size``,
this helper produces two parallel lists:
* ``coalesced_chunks`` – lengths of contiguous segments in the
**concatenated** sequence space, where each segment corresponds either
to a full chunk of size ``chunk_size`` or to a residual "epilogue"
tail shorter than ``chunk_size``.
* ``chunks`` – the actual chunk sizes used within each original sequence.
For a length ``n``, we produce ``n // chunk_size`` entries of
``chunk_size`` (the "prologue") and at most one final entry equal to
``n % chunk_size`` (the "epilogue").
``chunks`` reflects how each input length is decomposed into
fixed-size (plus optional tail) processing blocks, while
``coalesced_chunks`` describes those same blocks after concatenating consecutive
chunks of size ``chunk_size``. together
Example:
xs = [257, 127], chunk_size = 128
coalesced_chunks = [256, 1, 127]
chunks = [128, 128, 1, 127]
Args:
:param xs:
Iterable of non-negative integers
:param chunk_size:
Target chunk size
Returns:
:return Tuple[List[int], List[int]]:
``(coalesced_chunks, chunks)`` as described above.
"""
coalesced_chunks, chunks = [], []
for n in xs:
nchunks = n // chunk_size
prologue = nchunks * chunk_size
epilogue = n - prologue
if prologue > 0:
coalesced_chunks.append(prologue)
chunks.extend([chunk_size] * nchunks)
if epilogue > 0:
coalesced_chunks.append(epilogue)
chunks.append(epilogue)
return coalesced_chunks, chunks
def approximate_leverage_scores(
key_states: torch.Tensor, # [N, H, D]
context_lens: List[int], # [B]
PHI: torch.Tensor, # [D, k]
regularizer: float = 5e-3,
normalize: bool = False,
chunk_size: int = 512,
) -> torch.Tensor: # returns [N, H]
"""
Approximate leverage scores for keys via randomized sketching.
This implements a randomized approximation to per-token leverage scores for
the key matrix, as described in Compactor: Calibrated Query-Agnostic KV Cache
Compression with Approximate Leverage Scores (https://arxiv.org/abs/2507.08143).
Args:
:param key_states:
Tensor of shape ``[N, H, D]`` containing pre-RoPE key states for
all tokens across the batch, packed along the sequence dimension.
``N = sum(context_lens)``.
:param context_lens:
List of per-sequence context lengths, length ``B``.
:param PHI:
Random projection matrix of shape ``[D, k]`` used to sketch the
keys into a lower-dimensional subspace (k < D).
:param regularizer:
Small positive scalar added to the diagonal of each Gram matrix
before SVD to improve numerical stability. Defaults to ``1e-2``.
:param normalize:
If True, apply per-sequence z-score normalization to the scores
across all heads and tokens in a batch.
:param chunk_size:
Target chunk size along the sequence dimension. If > 0, the
concatenated sequence is split into chunks of at most this size
before forming Gram matrices and SVD. If ≤ 0, the entire sequence
for each context is treated as a single chunk.
Returns:
:return torch.Tensor:
Approximate leverage scores of shape ``[N, H]``, where each row
corresponds to a token and each column to a head.
"""
if chunk_size > 0:
coalesced_chunk_lens, chunks_lens = split_into_chunks(context_lens, chunk_size)
else:
coalesced_chunk_lens, chunks_lens = context_lens, context_lens
chunk_lens_cuda = torch.tensor([0] + chunks_lens).cuda(non_blocking=True)
X = torch.matmul(key_states.transpose(0, 1), PHI)
H, N, k = X.shape
chunks = torch.split(X, coalesced_chunk_lens, dim=-2)
gram_matrices = []
for i, L in enumerate(coalesced_chunk_lens):
chunk = chunks[i]
if chunk_size <= 0 or L % chunk_size != 0:
chunk.sub_(chunk.mean(dim=-2, keepdim=True))
g = torch.matmul(chunk.transpose(-1, -2), chunk) # [H, k, k]
g = g.unsqueeze(1)
else:
chunk = chunk.view(H, -1, chunk_size, k) # [H, num_chunks, chunk_size, k]
chunk.sub_(chunk.mean(dim=-2, keepdim=True))
g = torch.matmul(chunk.transpose(-1, -2), chunk) # [H, num_chunks, k, k]
gram_matrices.append(g)
G = torch.cat(gram_matrices, dim=1).to(torch.float32)
diag = G.diagonal(dim1=-2, dim2=-1)
diag.add_(regularizer)
try:
V, S, Vt = torch.linalg.svd(G, full_matrices=False, driver="gesvda")
except RuntimeError:
try:
diag = G.diagonal(dim1=-2, dim2=-1)
diag.add_(regularizer * 10)
V, S, Vt = torch.linalg.svd(G, full_matrices=False, driver="gesvda")
except RuntimeError:
with logging_redirect_tqdm():
logger.warning(
"GESVDA failed, falling back to QR decomposition, which will be MUCH slower. "
"Try increasing chunk_size if this issue persists."
)
# this is over 50 times slower than using GESVDA
return _approximate_leverage_scores_qr_fallback(
X=X,
chunks_lens=chunks_lens,
chunk_lens_cuda=chunk_lens_cuda,
normalize=normalize,
chunk_size=chunk_size,
)
SV = (V * S.rsqrt().unsqueeze(-2)).to(X.dtype)
start = 0
all_scores = []
for i, L in enumerate(coalesced_chunk_lens):
chunk = chunks[i]
if chunk_size <= 0 or L % chunk_size != 0:
num_chunks = 1
sv = SV[:, start]
else:
num_chunks = L // chunk_size
chunk = chunk.view(H, -1, chunk_size, k) # [H, NC, CS]
sv = SV[:, start : start + num_chunks]
U = torch.matmul(chunk, sv)
scores = (U * U).sum(dim=-1).clamp_min_(0.0).view(H, -1)
all_scores.append(scores.transpose(-1, -2))
start += num_chunks
scores = torch.cat(all_scores, dim=0)
if normalize:
grid = (len(chunks_lens),)
cu_k = chunk_lens_cuda.cumsum(dim=0)
_zscore_per_batch_epilogue_no_window[grid](
scores, cu_k, scores.stride(0), scores.stride(1), H
)
return scores
@triton_autotune(
configs=[triton.Config({"BLOCK_K": bk}) for bk in [32, 64, 128]],
key=["HK"],
cache_results=True,
)
@triton.jit
def _zscore_per_batch_epilogue_no_window(
OUT, # [Nk, Hk], float32
cu_k, # [B+1] int32
STRIDE_OUT_NK,
STRIDE_OUT_HK,
HK: tl.constexpr, # Hk
BLOCK_K: tl.constexpr, # e.g., 128
):
b = tl.program_id(0)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
if k_end <= k_beg:
return
sumv = tl.zeros([], dtype=tl.float32)
sumsq = tl.zeros([], dtype=tl.float32)
count = ((k_end - k_beg) * HK).to(tl.float32)
for ks in tl.range(k_beg, k_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_end
for h in tl.range(0, HK):
ptrs = OUT + nk * STRIDE_OUT_NK + h * STRIDE_OUT_HK
vals = tl.load(ptrs, mask=kmask, other=0.0).to(tl.float32)
sumv += tl.sum(vals, 0)
sumsq += tl.sum(vals * vals, 0)
mean = sumv / count
var = tl.maximum(sumsq / count - mean * mean, 0.0)
invstd = 1.0 / tl.sqrt(var)
for ks in tl.range(k_beg, k_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_end
for h in tl.range(0, HK):
ptrs = OUT + nk * STRIDE_OUT_NK + h * STRIDE_OUT_HK
vals = tl.load(ptrs, mask=kmask, other=0.0).to(tl.float32)
vals = (vals - mean) * invstd
tl.store(ptrs, vals, mask=kmask)
def _approximate_leverage_scores_qr_fallback(
X: torch.Tensor, # [H, N, k], already sketched (KΦ) and centered in-place
chunks_lens: List[int], # [num_chunks]
chunk_lens_cuda: torch.Tensor, # [num_chunks + 1] (prefix base)
normalize: bool,
chunk_size: int,
) -> torch.Tensor:
H, N, k = X.shape
device, dtype = X.device, X.dtype
offsets: List[int] = []
offset = 0
for L in chunks_lens:
offsets.append(offset)
offset += L
if offset != N:
raise RuntimeError(
f"QR fallback: sum(chunks_lens)={offset} does not match N={N}"
)
blocks = torch.split(X, chunks_lens, dim=-2)
scores = torch.empty(N, H, device=device, dtype=dtype)
if chunk_size > 0:
full_indices = [i for i, L in enumerate(chunks_lens) if L == chunk_size]
epi_indices = [i for i, L in enumerate(chunks_lens) if L != chunk_size]
if full_indices:
# stack full chunks
full_blocks = torch.stack(
[blocks[i] for i in full_indices], dim=0
) # [M, H, CS, k]
M, Hf, Lf, kf = full_blocks.shape
assert Lf == chunk_size
# merge (M, H) into a single batch dim for torch.linalg.q
full_blocks_2d = full_blocks.view(M * Hf, Lf, kf).to(torch.float32)
U_full, _ = torch.linalg.qr(full_blocks_2d, mode="reduced")
U_full = U_full.to(dtype)
scores_full = (U_full * U_full).sum(dim=-1).clamp_min(0.0) # [M * Hf, Lf]
scores_full = scores_full.view(M, Hf, Lf).transpose(-1, -2) # [M, H, CS]
for m, chunk_idx in enumerate(full_indices):
start = offsets[chunk_idx]
Lc = chunks_lens[chunk_idx]
scores[start : start + Lc].copy_(scores_full[m])
else:
epi_indices = list(range(len(chunks_lens)))
for chunk_idx in epi_indices:
block = blocks[chunk_idx]
_, Lc, _ = block.shape
if Lc == 0:
continue
U_epi, _ = torch.linalg.qr(block.to(torch.float32), mode="reduced")
scores_epi = (U_epi * U_epi).sum(dim=-1).to(dtype) # [H, Lc]
start = offsets[chunk_idx]
scores[start : start + Lc] = scores_epi.transpose(0, 1) # [Lc, H]
if normalize:
grid = (len(chunks_lens),)
cu_k = chunk_lens_cuda.cumsum(dim=0)
_zscore_per_batch_epilogue_no_window[grid](
scores, cu_k, scores.stride(0), scores.stride(1), H
)
return scores
@triton_autotune(
configs=[
triton.Config(
{"BLOCK_M": BM, "BLOCK_K": BK, "WARPSPEC": False}, num_warps=w, num_stages=s
)
for BM in [64]
for BK in [64]
for w in [4]
for s in [2]
],
key=[
"QUERY_GROUP_SIZE",
"D",
"CHUNK_SIZE",
],
cache_results=True,
)
@triton.jit
def _non_causal_attn_kernel(
Q,
K,
V,
accum_scores,
cu_seqlens_qk,
#
STRIDE_Q_G,
STRIDE_Q_N,
STRIDE_Q_H,
STRIDE_Q_D,
STRIDE_K_G,
STRIDE_K_N,
STRIDE_K_D,
STRIDE_V_G,
STRIDE_V_N,
STRIDE_V_D,
STRIDE_OUT_N,
STRIDE_OUT_H,
sm_scale,
#
CHUNK_SIZE: tl.constexpr,
QUERY_GROUP_SIZE: tl.constexpr,
BLOCK_M: tl.constexpr,
BLOCK_K: tl.constexpr,
D: tl.constexpr,
WARPSPEC: tl.constexpr,
):
TOTAL_QUERIES_PER_BLOCK: tl.constexpr = BLOCK_M * QUERY_GROUP_SIZE
INVERSE_CHUNK: tl.constexpr = 1.0 / CHUNK_SIZE
pid_g = tl.program_id(0) # KV head in [0, HKV)
pid_b = tl.program_id(1) # batch id
pid_m = tl.program_id(2) # chunk id within batch
off_b = tl.load(cu_seqlens_qk + pid_b)
off_b1 = tl.load(cu_seqlens_qk + pid_b + 1)
chunk_start = off_b + pid_m * CHUNK_SIZE
chunk_end = tl.minimum(chunk_start + CHUNK_SIZE, off_b1)
M = chunk_end - chunk_start
if M <= 0:
return
offs_d = tl.arange(0, D)
offs_k = tl.arange(0, BLOCK_K)
# Flattened query rows inside a [BLOCK_M, QUERY_GROUP_SIZE] tile
offs_q = tl.arange(0, TOTAL_QUERIES_PER_BLOCK)
row_m = offs_q % BLOCK_M # token offset in this tile
row_h = offs_q // BLOCK_M # query-group index
qk_scale = sm_scale * 1.44269504 # convert to log2-domain
NEG_INF = -1.0e9
# Iterate over query tiles within this chunk
for qs in tl.range(chunk_start, chunk_end, BLOCK_M):
# Global query indices for rows in this tile
q_idx = qs + row_m # [TOTAL_QUERIES_PER_BLOCK]
q_mask = q_idx < chunk_end # mask for valid rows in this tile
# Load Q tile: [TOTAL_QUERIES_PER_BLOCK, D]
q_ptrs = (
Q
+ pid_g * STRIDE_Q_G
+ q_idx[:, None] * STRIDE_Q_N
+ row_h[:, None] * STRIDE_Q_H
+ offs_d[None, :] * STRIDE_Q_D
)
q = tl.load(q_ptrs, mask=q_mask[:, None], other=0.0)
# ---- Pass 1: per-row max and denominator over all keys in this chunk ----
row_max = tl.full([TOTAL_QUERIES_PER_BLOCK], NEG_INF, tl.float32)
row_sum = tl.zeros([TOTAL_QUERIES_PER_BLOCK], dtype=tl.float32)
for ks in tl.range(chunk_start, chunk_end, BLOCK_K):
k_idx = ks + offs_k # [BLOCK_K]
k_mask = k_idx < chunk_end # which keys are valid in this tile
k_ptrs = (
K
+ pid_g * STRIDE_K_G
+ k_idx[:, None] * STRIDE_K_N
+ offs_d[None, :] * STRIDE_K_D
)
k = tl.load(k_ptrs, mask=k_mask[:, None], other=0.0) # [BLOCK_K, D]
# logits: [TOTAL_QUERIES_PER_BLOCK, BLOCK_K]
qk = tl.dot(q, k.T) * qk_scale
qk = tl.where(q_mask[:, None] & k_mask[None, :], qk, NEG_INF)
cur_max = tl.max(qk, 1)
new_max = tl.maximum(row_max, cur_max)
# rescale previous sum to new_max (base 2)
rescale = tl.math.exp2(row_max - new_max)
p = tl.math.exp2(qk - new_max[:, None])
row_sum = row_sum * rescale + tl.sum(p, 1)
row_max = new_max
# Avoid division by zero for inactive rows
denom = tl.where(q_mask, row_sum, 1.0)
for ks in tl.range(chunk_start, chunk_end, BLOCK_K):
k_idx = ks + offs_k
k_mask = k_idx < chunk_end
k_ptrs = (
K
+ pid_g * STRIDE_K_G
+ k_idx[:, None] * STRIDE_K_N
+ offs_d[None, :] * STRIDE_K_D
)
k = tl.load(k_ptrs, mask=k_mask[:, None], other=0.0)
qk = tl.dot(q, k.T) * qk_scale
qk = tl.where(q_mask[:, None] & k_mask[None, :], qk, NEG_INF)
# p has shape [TOTAL_QUERIES_PER_BLOCK, BLOCK_K]
p = tl.math.exp2(qk - row_max[:, None]) / denom[:, None]
# zero-out invalid rows / columns
p = tl.where(
q_mask[:, None], p, INVERSE_CHUNK
) # preserve attention mass in shorter chunks
contrib = tl.sum(p, 0) # [BLOCK_K], sum over queries & query-groups
out_ptrs = accum_scores + k_idx * STRIDE_OUT_N + pid_g * STRIDE_OUT_H
old = tl.load(out_ptrs, mask=k_mask, other=0.0)
new = old + contrib.to(old.dtype)
tl.store(out_ptrs, new, mask=k_mask)
def non_causal_attn_scores(
q: torch.Tensor, # [N, HQ, D]
k: torch.Tensor, # [N, HKV, D]
v: torch.Tensor, # [N, HKV, D]
cu_seqlens_qk: torch.Tensor, # [B + 1]
max_seqlen_qk: int,
chunk_size: int,
sm_scale: float = None,
normalize: bool = True,
context_lens: Optional[List[int]] = None,
protected_first_tokens: Optional[List[int]] = None,
protected_last_tokens: Optional[List[int]] = None,
*,
accum_scores: torch.Tensor = None, # [N, HKV] (float32)
accum_blending: float = None,
) -> torch.Tensor:
"""
:param q: Tensor of shape ``[N, H, D]`` containing post-rope queries
:param k: Tensor of shape ``[N, H, D]`` containing post-rope keys
:param v: Tensor of shape ``[N, H, D]`` containing values
:param cu_seqlens_qk Tensor of shape ``[B + 1]`` demarcating batch boundaries
:param max_seqlen_qk int containing the maximum sequence length
:param chunk_size: int specifying the size of the chunk to perform non-causal attention over
:param sm_scale: float specifying the scaling factor applied to attention scores (1/sqrt(D) if None)
:param normalize: bool specifying whether to z-score normalize final attention scores
:param context_lens: List[int] specifying the context lengths. CPU version of cu_seqlens_qk.diff(0)
:param protected_first_tokens: List[int] specifying how many tokens should be protected at the
start of each sequence
:param protected_last_tokens: List[int] specifying how many tokens should be protected at the
end of each sequence
:param accum_scores: Tensor of shape ``[N, H]`` containing key scores that should be accumulated into
:param accum_blending float specifying the scaling of ``accum_scores`` prior to adding the new
non-causal attention scores. Final output is equivalent to return out + accum_blending * accum_scores
"""
assert q.ndim == 3 and k.ndim == 3
assert q.shape[0] == k.shape[0] and q.shape[-1] == k.shape[-1]
N, HQ, D = q.shape
HKV = k.shape[1]
assert HQ % HKV == 0, "Number of query heads must divide number of KV heads"
assert (D & (D - 1)) == 0, "D must be a power of two"
B = cu_seqlens_qk.numel() - 1
H_g = HQ // HKV # query-group size per KV head
if sm_scale is None:
sm_scale = 1.0 / math.sqrt(D)
out = torch.zeros(N, HKV, device=q.device, dtype=torch.float32)
q = q.view(N, HKV, H_g, D).permute(1, 0, 2, 3)
k = k.view(N, HKV, D).permute(1, 0, 2)
# v = v.view(N, HKV, D).permute(1, 0, 2)
if cu_seqlens_qk.device != q.device:
cu_seqlens_qk = cu_seqlens_qk.to(device=q.device)
cu_seqlens_qk = cu_seqlens_qk.to(torch.int32)
STRIDE_Q_G, STRIDE_Q_N, STRIDE_Q_H, STRIDE_Q_D = q.stride()
STRIDE_K_G, STRIDE_K_N, STRIDE_K_D = k.stride()
STRIDE_V_G, STRIDE_V_N, STRIDE_V_D = v.stride()
STRIDE_OUT_N, STRIDE_OUT_H = out.stride()
assert STRIDE_Q_D == 1 and STRIDE_K_D == 1, "last dim must be contiguous"
def grid(_):
return (
HKV,
B,
triton.cdiv(max_seqlen_qk, chunk_size),
)
_non_causal_attn_kernel[grid](
q,
k,
v,
out,
cu_seqlens_qk,
STRIDE_Q_G,
STRIDE_Q_N,
STRIDE_Q_H,
STRIDE_Q_D,
STRIDE_K_G,
STRIDE_K_N,
STRIDE_K_D,
STRIDE_V_G,
STRIDE_V_N,
STRIDE_V_D,
STRIDE_OUT_N,
STRIDE_OUT_H,
sm_scale,
CHUNK_SIZE=chunk_size,
QUERY_GROUP_SIZE=H_g,
D=D,
)
if normalize:
grid = (B,)
_zscore_per_batch_epilogue_no_window[grid](
out, cu_seqlens_qk, out.stride(0), out.stride(1), HKV
)
if accum_scores is not None:
if accum_blending is not None:
out += accum_scores * accum_blending
else:
out += accum_scores
if protected_first_tokens is not None or protected_last_tokens is not None:
start = 0
for first, last, L in zip(
protected_first_tokens, protected_last_tokens, context_lens
):
out[start : start + first].fill_(torch.inf)
out[start + L - last : start + L].fill_(torch.inf)
start += L
return out
import logging
from dataclasses import dataclass
from enum import Enum, auto
logger = logging.getLogger(__name__)
class CompressionMethod(Enum):
CRITICALADAKV = auto()
COMPACTOR = auto()
SNAPKV = auto()
NONE = auto()
# class CachingPolicy(Enum):
# CACHE_PROMPT = auto()
# DONT_CACHE = auto()
# class CompressionType(Enum):
# QUERY_AWARE = auto()
# QUERY_AGNOSTIC = auto()
@dataclass
class SequenceCompressionParams:
compression_ratio: float = 1.0
protected_first_tokens: int = 16
protected_last_tokens: int = 64
@dataclass
class BatchCompressionParams:
# compression_type: CompressionType = CompressionType.QUERY_AGNOSTIC
compression_method: CompressionMethod = CompressionMethod.COMPACTOR
do_chunked_compression: bool = True
chunk_size: int = 512
def __post_init__(self):
if self.compression_method == CompressionMethod.SNAPKV:
self.do_chunked_compression = False
logger.warning(
"CompressionMethod.SNAPKV is not compatible with chunked compression. Disabling it."
)
"""
CriticalAdaKV: 在 Compactor(pre RoPE 杠杆分 + post RoPE 非因果注意力融合)基础上,
用输出投影 Wo 对 Value 的 L1 范数做 Stage-2 重加权;Stage-1 在 Compactor 基础分上做预算内 top-k 保护。
预算与 compactor_vllm 引擎一致:使用 ``compression_context.batch_tokens_to_retain``(flatten 的
(token, head) 对数量)及首/尾保护段长度。
注意:不得在 import 时加载 ``compactor_vllm.utils.context``(其会再 import ``CompressionMethod``,
与 ``compression/__init__.py`` 导入本模块形成环)。运行时只使用与 ``CompressionContext`` 同字段的 duck 对象。
"""
from __future__ import annotations
from typing import Any, Optional, Tuple
import torch
import triton
from triton import language as tl
from compactor_vllm.compression.common import BaseCompressionMethod
from compactor_vllm.compression.compactor import (
CompactorCompression,
non_causal_attn_scores,
)
from compactor_vllm.compression.snapkv import SnapKVCompression
from compactor_vllm.utils.helpers import maybe_execute_in_stream
from compactor_vllm.utils.triton_compat import autotune as triton_autotune
# ============================================================================
# Triton Kernel 1: 计算 ||Wo @ V||₁ (L1 范数)
# ============================================================================
@triton_autotune(
configs=[
triton.Config({"BLOCK_K": bk, "BLOCK_D": bd}, num_warps=nw, num_stages=ns)
for bk in [32, 64, 128]
for bd in [32, 64]
for nw in [4, 8]
for ns in [3, 4]
],
key=["Hk", "D", "HIDDEN"],
cache_results=True,
)
@triton.jit
def _compute_wo_v_l1_kernel(
V,
WO,
cu_k,
OUT,
STRIDE_V_NK,
STRIDE_V_HK,
STRIDE_V_D,
STRIDE_WO_HQ,
STRIDE_WO_D,
STRIDE_WO_HID,
STRIDE_OUT_NK,
STRIDE_OUT_HK,
Hk: tl.constexpr,
Hq: tl.constexpr,
D: tl.constexpr,
HIDDEN: tl.constexpr,
QUERY_GROUP_SIZE: tl.constexpr,
BLOCK_K: tl.constexpr,
BLOCK_D: tl.constexpr,
):
b = tl.program_id(0)
hk = tl.program_id(1)
ks = tl.program_id(2)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
nk_off = ks * BLOCK_K + tl.arange(0, BLOCK_K)
nk = k_beg + nk_off
k_mask = nk < k_end
out_ptrs = OUT + nk * STRIDE_OUT_NK + hk * STRIDE_OUT_HK
l1_sum = tl.zeros([BLOCK_K], dtype=tl.float32)
for g in range(QUERY_GROUP_SIZE):
hq = hk * QUERY_GROUP_SIZE + g
v_ptrs = (
V
+ nk[:, None] * STRIDE_V_NK
+ hk * STRIDE_V_HK
+ tl.arange(0, D)[None, :] * STRIDE_V_D
)
v_blk = tl.load(v_ptrs, mask=k_mask[:, None], other=0.0).to(tl.float32)
for hid_off in range(0, HIDDEN, BLOCK_D):
hid_idx = hid_off + tl.arange(0, BLOCK_D)
hid_mask = hid_idx < HIDDEN
wo_ptrs = (
WO
+ hq * STRIDE_WO_HQ
+ tl.arange(0, D)[:, None] * STRIDE_WO_D
+ hid_idx[None, :] * STRIDE_WO_HID
)
wo_tile = tl.load(wo_ptrs, mask=hid_mask[None, :], other=0.0).to(tl.float32)
wov_tile = tl.dot(v_blk, wo_tile)
l1_sum += tl.sum(tl.abs(wov_tile), axis=1)
l1_sum = l1_sum / QUERY_GROUP_SIZE
tl.store(out_ptrs, l1_sum, mask=k_mask)
# ============================================================================
# Triton Kernel 2: Stage 1 保护 + Stage 2 加权融合
# ============================================================================
@triton_autotune(
configs=[triton.Config({"BLOCK_K": bk}) for bk in [32, 64, 128, 256]],
key=["Hk"],
cache_results=True,
)
@triton.jit
def _critical_ada_fuse_kernel(
BASE_SCORES,
WO_V_NORM,
STAGE1_MASK,
cu_k,
OUT,
EPSILON: tl.constexpr,
STRIDE_BS_NK,
STRIDE_BS_HK,
STRIDE_WN_NK,
STRIDE_WN_HK,
STRIDE_S1_NK,
STRIDE_S1_HK,
STRIDE_OUT_NK,
STRIDE_OUT_HK,
Hk: tl.constexpr,
BLOCK_K: tl.constexpr,
):
b = tl.program_id(0)
hk = tl.program_id(1)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
for ks in tl.range(k_beg, k_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_end
bs_ptrs = BASE_SCORES + nk * STRIDE_BS_NK + hk * STRIDE_BS_HK
wn_ptrs = WO_V_NORM + nk * STRIDE_WN_NK + hk * STRIDE_WN_HK
s1_ptrs = STAGE1_MASK + nk * STRIDE_S1_NK + hk * STRIDE_S1_HK
base = tl.load(bs_ptrs, mask=kmask, other=0.0)
wnorm = tl.load(wn_ptrs, mask=kmask, other=1.0)
stage1_protect = tl.load(s1_ptrs, mask=kmask, other=0).to(tl.int32)
fused = (base + EPSILON) * wnorm
fused = tl.where(stage1_protect == 1, float("inf"), fused)
out_ptrs = OUT + nk * STRIDE_OUT_NK + hk * STRIDE_OUT_HK
tl.store(out_ptrs, fused, mask=kmask)
def critical_ada_key_scores(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
wo_weight: torch.Tensor,
cu_seqlens: torch.Tensor,
base_scores: torch.Tensor,
compression_ctx: Any,
*,
store_stream: Optional[torch.cuda.Stream] = None,
) -> Tuple[torch.Tensor, Optional[Tuple[torch.Tensor, torch.Tensor, torch.Tensor]]]:
"""
使用与引擎一致的保留预算 ``batch_tokens_to_retain``(每条序列的 (token, head) 对数),
在每条序列上尽量贴近 kvpress 的 CriticalAdaKV 语义:
1) alpha_safeguard 安全预算(每头至少保留一部分);
2) 基于 base_scores 的 head-wise 自适应预算分配(head_budgets);
3) Stage-1 按 head_budgets * first_stage_ratio 保护;
4) Stage-2 计算 ``(base + eps) * ||Wo@V||_1``,再按 head_budgets 做每头 top-k 保护。
Args:
compression_ctx: 与 ``CompressionContext`` 相同字段即可(duck typing),须含
``batch_tokens_to_retain``、``protected_first_tokens``、``protected_last_tokens``;
可选 ``critical_ada_epsilon``、``critical_ada_first_stage_ratio``、
``critical_ada_alpha_safeguard``。
"""
assert q.stride(-1) == 1 and k.stride(-1) == 1 and v.stride(-1) == 1
device = q.device
_, Hq, D = q.shape
N_k, Hk, Dk = k.shape
assert D == Dk and Hq % Hk == 0
# 与 non_causal_attn_scores 使用同一 cu(prefill 下即 context.cu_seqlens_q),
# 保证 base_scores 行与 Triton 分段一致;勿与 cu_seqlens_k 混用。
B = cu_seqlens.numel() - 1
G = Hq // Hk
k_lengths = cu_seqlens[1:] - cu_seqlens[:-1]
btr = compression_ctx.batch_tokens_to_retain
assert btr is not None and btr.numel() == B
btr = btr.to(device=device, dtype=torch.int32)
prot_first = compression_ctx.protected_first_tokens or [0] * B
prot_last = compression_ctx.protected_last_tokens or [0] * B
epsilon = compression_ctx.critical_ada_epsilon
first_stage_ratio = compression_ctx.critical_ada_first_stage_ratio
alpha_safeguard = float(getattr(compression_ctx, "critical_ada_alpha_safeguard", 0.2))
alpha_safeguard = max(0.0, min(1.0, alpha_safeguard))
if wo_weight.dim() == 2:
hidden_size, _ = wo_weight.shape
wo = wo_weight.transpose(0, 1).view(Hq, D, hidden_size).contiguous()
else:
wo = wo_weight.contiguous()
hidden_size = wo.size(-1)
wo_v_norm = torch.empty((N_k, Hk), dtype=torch.float32, device=device)
def grid_wo(META):
max_k_len = int(k_lengths.max().item())
return (B, Hk, triton.cdiv(max_k_len, META["BLOCK_K"]))
_compute_wo_v_l1_kernel[grid_wo](
v,
wo,
cu_seqlens,
wo_v_norm,
*v.stride(),
*wo.stride(),
*wo_v_norm.stride(),
Hk=Hk,
Hq=Hq,
D=D,
HIDDEN=hidden_size,
QUERY_GROUP_SIZE=G,
)
stage1_mask = torch.zeros((N_k, Hk), dtype=torch.int32, device=device)
# kvpress 风格的每头预算(按序列自适应),用于 Stage-1/Stage-2。
head_budgets_by_batch = []
for b in range(B):
k_len = int(k_lengths[b].item())
if k_len == 0:
head_budgets_by_batch.append(None)
continue
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
s = int(prot_first[b]) if b < len(prot_first) else 0
e = int(prot_last[b]) if b < len(prot_last) else 0
lo, hi = k_beg + s, k_end - e
compressible = max(0, hi - lo)
keep_pairs = int(btr[b].item())
if compressible <= 0:
head_budgets_by_batch.append(None)
continue
# 每头 token 预算(kvpress 的 n_kept)
n_kept_tokens = max(1, keep_pairs // Hk)
n_kept_tokens = min(n_kept_tokens, compressible)
# 安全预算(每头至少保留 n_safe)
n_safe = int(n_kept_tokens * alpha_safeguard)
if n_safe > 0:
tk_safe = min(n_safe, compressible)
for hk in range(Hk):
safe_idx = torch.topk(base_scores[lo:hi, hk], tk_safe, sorted=False).indices
stage1_mask[lo + safe_idx, hk] = 1
# 自适应预算分配:在扁平 (token, head) 空间取 top n_kept_tokens*Hk,统计每个 head 的预算
budget_scores = base_scores[lo:hi, :].clone()
if n_safe > 0:
budget_scores[stage1_mask[lo:hi, :] == 1] = float("inf")
top_pairs = min(n_kept_tokens * Hk, budget_scores.numel())
if top_pairs <= 0:
head_budgets_by_batch.append(None)
continue
top_idx_flat = torch.topk(
budget_scores.reshape(-1), top_pairs, sorted=False
).indices
top_head_idx = top_idx_flat % Hk
head_budgets = torch.bincount(top_head_idx, minlength=Hk).to(torch.int32)
head_budgets_by_batch.append(head_budgets)
# Stage-1:按 head_budgets 的 first_stage_ratio 分头保护(kvpress 语义)
for hk in range(Hk):
phase1_budget = int(head_budgets[hk].item() * first_stage_ratio)
if phase1_budget <= 0:
continue
tk = min(phase1_budget, compressible)
top_idx = torch.topk(base_scores[lo:hi, hk], tk, sorted=False).indices
stage1_mask[lo + top_idx, hk] = 1
final_scores = torch.empty((N_k, Hk), dtype=torch.float32, device=device)
def grid_fuse(_META):
return (B, Hk)
_critical_ada_fuse_kernel[grid_fuse](
base_scores,
wo_v_norm,
stage1_mask,
cu_seqlens,
final_scores,
EPSILON=epsilon,
*base_scores.stride(),
*wo_v_norm.stride(),
*stage1_mask.stride(),
*final_scores.stride(),
Hk=Hk,
)
# Stage-2(kvpress 语义):在融合后按每头预算再做一次 top-k 保护。
for b in range(B):
hb = head_budgets_by_batch[b]
if hb is None:
continue
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
s = int(prot_first[b]) if b < len(prot_first) else 0
e = int(prot_last[b]) if b < len(prot_last) else 0
lo, hi = k_beg + s, k_end - e
if hi <= lo:
continue
region_len = hi - lo
for hk in range(Hk):
budget = int(hb[hk].item())
if budget <= 0:
continue
tk = min(budget, region_len)
idx = torch.topk(final_scores[lo:hi, hk], tk, sorted=False).indices
final_scores[lo + idx, hk] = float("inf")
masked_key_indices = None
for b in range(B):
k_len = int(k_lengths[b].item())
if k_len == 0:
continue
keep_pairs = int(btr[b].item())
total_pairs = k_len * Hk
if keep_pairs >= total_pairs:
continue
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
n_prune_pairs = min(total_pairs - keep_pairs, total_pairs)
if n_prune_pairs <= 0:
continue
flat_scores = final_scores[k_beg:k_end, :].reshape(-1)
prune_idx = torch.topk(
-flat_scores, min(n_prune_pairs, flat_scores.numel()), sorted=False
).indices
batch_idx = torch.full_like(prune_idx, b, dtype=torch.int64)
head_idx = prune_idx % Hk
seq_idx = prune_idx // Hk + k_beg
if masked_key_indices is None:
masked_key_indices = (batch_idx, head_idx, seq_idx)
else:
masked_key_indices = (
torch.cat([masked_key_indices[0], batch_idx]),
torch.cat([masked_key_indices[1], head_idx]),
torch.cat([masked_key_indices[2], seq_idx]),
)
if store_stream is not None:
final_scores.record_stream(store_stream)
return final_scores, masked_key_indices
class CriticalAdaKVCompression(BaseCompressionMethod):
"""
以 CompactorCompression 为基分(pre RoPE 杠杆 + post RoPE 非因果融合),
再应用 CriticalAda 两阶段加权;须由 Attention 在 post-RoPE 前注入 ``compression_context.wo_weight``。
"""
@staticmethod
def pre_rope_scoring(
q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, context
) -> Optional[torch.Tensor]:
cc = context.compression_context
base = getattr(cc, "critical_ada_base_scorer", "compactor") if cc is not None else "compactor"
if str(base).lower() == "snapkv":
return SnapKVCompression.pre_rope_scoring(q, k, v, context)
return CompactorCompression.pre_rope_scoring(q, k, v, context)
@staticmethod
def post_rope_scoring(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
pre_rope_scores: Optional[torch.Tensor],
context,
) -> Optional[torch.Tensor]:
compression_context = context.compression_context
assert compression_context is not None
base = str(getattr(compression_context, "critical_ada_base_scorer", "compactor")).lower()
if base == "snapkv":
base_scores = SnapKVCompression.post_rope_scoring(q, k, v, pre_rope_scores, context)
else:
# 与 compactor.py 中 CompactorCompression.post_rope_scoring 逐字一致:
# maybe_execute_in_stream(non_causal_attn_scores, q,k,v, cu_seqlens_q, max_seqlen_q, ...)
# 不得改为其它封装,否则与单独使用 COMPACTOR 时分数字不一致。
if context.STORE_STREAM is not None:
torch.cuda.current_stream().wait_stream(context.STORE_STREAM)
base_scores = maybe_execute_in_stream(
non_causal_attn_scores,
q,
k,
v,
context.cu_seqlens_q,
context.max_seqlen_q,
chunk_size=CompactorCompression.chunk_size,
sm_scale=1.0,
normalize=True,
accum_scores=pre_rope_scores,
context_lens=compression_context.context_lens,
protected_first_tokens=compression_context.protected_first_tokens,
protected_last_tokens=compression_context.protected_last_tokens,
accum_blending=0.5,
)
wo_weight = compression_context.wo_weight
if wo_weight is None:
return base_scores
scores, _masked = maybe_execute_in_stream(
critical_ada_key_scores,
q,
k,
v,
wo_weight,
context.cu_seqlens_q,
base_scores,
compression_context,
STORE_STREAM=context.STORE_STREAM,
store_stream=context.STORE_STREAM,
)
return scores
@staticmethod
def prepare_layer(module: torch.nn.Module, device: torch.device, dtype: torch.dtype):
"""可选:预计算并缓存 Wo;实际推理以 Attention.forward 中注入的 ``cc.wo_weight`` 为准。"""
if not hasattr(module, "o_proj") or module.o_proj.weight is None:
return
if not hasattr(module, "num_heads") or not hasattr(module, "head_dim"):
return
wo_raw = module.o_proj.weight.data
hidden_size, _ = wo_raw.shape
Hq = module.num_heads
head_dim = module.head_dim
wo = (
wo_raw.transpose(0, 1)
.view(Hq, head_dim, hidden_size)
.to(device=device, dtype=torch.float32)
)
module._critical_ada_wo_weight = wo
"""
CriticalAdaKV: 在 Compactor(pre RoPE 杠杆分 + post RoPE 非因果注意力融合)基础上,
用输出投影 Wo 对 Value 的 L1 范数做 Stage-2 重加权;Stage-1 在 Compactor 基础分上做预算内 top-k 保护。
预算与 vllm.kvprune 引擎一致:使用 ``compression_context.batch_tokens_to_retain``(flatten 的
(token, head) 对数量)。CriticalAda 主链在 **PyTorch** 中与 kvpress ``CriticalAdaKVPress.compress``
对齐;``||Wo@V||_1`` 仍默认用 Triton ``_compute_wo_v_l1_kernel``(与 ``CriticalKVPress.vwl1norm`` 同式)。
将 ``_USE_WO_L1_REFERENCE_BACKEND`` 置为 ``True`` 可改走 ``_vwl1_norm_kvpress_reference``。
注意:不得在 import 时加载 ``vllm.kvprune.utils.context``(其会再 import ``CompressionMethod``,
与 ``compression/__init__.py`` 导入本模块形成环)。运行时只使用与 ``CompressionContext`` 同字段的 duck 对象。
"""
from __future__ import annotations
from typing import Any, Optional, Tuple
import torch
import triton
from triton import language as tl
from transformers.models.llama.modeling_llama import repeat_kv
from compactor_vllm.compression.common import BaseCompressionMethod
from compactor_vllm.compression.compactor import (
CompactorCompression,
kvpress_compactor_post_rope,
resolve_kvpress_compactor_blending,
)
from compactor_vllm.compression.snapkv import SnapKVCompression
from compactor_vllm.utils.helpers import maybe_execute_in_stream
from compactor_vllm.utils.triton_compat import autotune as triton_autotune
# Wo@V 的 L1:False = Triton(默认),True = PyTorch 参考(调试/对齐)
_USE_WO_L1_REFERENCE_BACKEND = False
def _vwl1_norm_kvpress_reference(
values_seg: torch.Tensor,
wo: torch.Tensor,
num_kv_heads: int,
num_query_groups: int,
) -> torch.Tensor:
"""
与 kvpress ``CriticalKVPress.vwl1norm`` 等价的 **可选参考实现**(PyTorch,仅用于核对;
将 ``_USE_WO_L1_REFERENCE_BACKEND`` 置为 ``True`` 时选用,默认走 Triton)。
算法:repeat_kv → 逐 query 头 ``|V @ Wo_h|_1`` → 在 GQA 组上 mean,与 Triton 路径同一公式。
"""
k_len, Hk, D = values_seg.shape
Hq, D_wo, hidden = wo.shape
assert D == D_wo and Hk == num_kv_heads and Hq == Hk * num_query_groups
# [1, Hk, k_len, D] 与 HF repeat_kv 约定一致
v_4d = values_seg.permute(1, 0, 2).unsqueeze(0).contiguous()
v_rep = repeat_kv(v_4d, num_query_groups) # [1, Hq, k_len, D]
# Wo 在 attention 里注入为 float32,V 常为 bf16/fp16,matmul 前对齐 dtype
wo_f = wo
head_list = []
for head in range(Hq):
v_h = v_rep[0, head, :, :].to(dtype=wo_f.dtype)
head_wov = v_h.matmul(wo_f[head, :, :])
head_wov_norm = torch.norm(head_wov, p=1, dim=-1)
head_list.append(head_wov_norm)
stacked = torch.stack(head_list, dim=0) # [Hq, k_len]
stacked = stacked.view(Hk, num_query_groups, k_len).mean(dim=1)
return stacked.transpose(0, 1).contiguous()
# ============================================================================
# Triton:||Wo @ V||₁ 按 kvpress 定义(GQA 上对 query 组 L1 后取均值)
# ============================================================================
@triton_autotune(
configs=[
triton.Config({"BLOCK_K": bk, "BLOCK_D": bd}, num_warps=nw, num_stages=ns)
for bk in [32, 64, 128]
for bd in [32, 64]
for nw in [4, 8]
for ns in [3, 4]
],
key=["Hk", "D", "HIDDEN"],
cache_results=True,
)
@triton.jit
def _compute_wo_v_l1_kernel(
V,
WO,
cu_k,
OUT,
STRIDE_V_NK,
STRIDE_V_HK,
STRIDE_V_D,
STRIDE_WO_HQ,
STRIDE_WO_D,
STRIDE_WO_HID,
STRIDE_OUT_NK,
STRIDE_OUT_HK,
Hk: tl.constexpr,
Hq: tl.constexpr,
D: tl.constexpr,
HIDDEN: tl.constexpr,
QUERY_GROUP_SIZE: tl.constexpr,
BLOCK_K: tl.constexpr,
BLOCK_D: tl.constexpr,
):
"""对每个 KV 头:对 G 个 query 头分别算 ``sum(|V @ Wo|)``,再除以 G(与 kvpress mean 一致)。"""
b = tl.program_id(0)
hk = tl.program_id(1)
ks = tl.program_id(2)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
nk_off = ks * BLOCK_K + tl.arange(0, BLOCK_K)
nk = k_beg + nk_off
k_mask = nk < k_end
out_ptrs = OUT + nk * STRIDE_OUT_NK + hk * STRIDE_OUT_HK
l1_sum = tl.zeros([BLOCK_K], dtype=tl.float32)
for g in range(QUERY_GROUP_SIZE):
hq = hk * QUERY_GROUP_SIZE + g
v_ptrs = (
V
+ nk[:, None] * STRIDE_V_NK
+ hk * STRIDE_V_HK
+ tl.arange(0, D)[None, :] * STRIDE_V_D
)
v_blk = tl.load(v_ptrs, mask=k_mask[:, None], other=0.0).to(tl.float32)
for hid_off in range(0, HIDDEN, BLOCK_D):
hid_idx = hid_off + tl.arange(0, BLOCK_D)
hid_mask = hid_idx < HIDDEN
wo_ptrs = (
WO
+ hq * STRIDE_WO_HQ
+ tl.arange(0, D)[:, None] * STRIDE_WO_D
+ hid_idx[None, :] * STRIDE_WO_HID
)
wo_tile = tl.load(wo_ptrs, mask=hid_mask[None, :], other=0.0).to(tl.float32)
wov_tile = tl.dot(v_blk, wo_tile)
l1_sum += tl.sum(tl.abs(wov_tile), axis=1)
l1_sum = l1_sum / QUERY_GROUP_SIZE
tl.store(out_ptrs, l1_sum, mask=k_mask)
def critical_ada_key_scores(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
wo_weight: torch.Tensor,
cu_seqlens: torch.Tensor,
base_scores: torch.Tensor,
compression_ctx: Any,
*,
store_stream: Optional[torch.cuda.Stream] = None,
) -> Tuple[torch.Tensor, Optional[Tuple[torch.Tensor, torch.Tensor, torch.Tensor]]]:
"""
使用与引擎一致的保留预算 ``batch_tokens_to_retain``(每条序列的 (token, head) 对数),
按 kvpress ``CriticalAdaKVPress.compress`` 的顺序实现:safeguard scatter →
head-major 展平做 head_budgets → Stage1 在 **已抬高** 的分数上 top-k →
``(scores + ε) * ||WoV||₁`` → Stage2 scatter → 最终按 head-major 展平做 bottom-k。
``||Wo@V||₁`` 仍用 Triton(``_compute_wo_v_l1_kernel``);中间 CriticalAda 步骤用 PyTorch
与 kvpress 逐句对齐。仅 base 分数来自 Compactor/SnapKV。
Args:
compression_ctx: 与 ``CompressionContext`` 相同字段即可(duck typing),须含
``batch_tokens_to_retain``;可选 ``critical_ada_epsilon``、
``critical_ada_first_stage_ratio``、``critical_ada_alpha_safeguard``。
"""
assert q.stride(-1) == 1 and k.stride(-1) == 1 and v.stride(-1) == 1
device = q.device
_, Hq, D = q.shape
N_k, Hk, Dk = k.shape
assert D == Dk and Hq % Hk == 0
# 与 non_causal_attn_scores 使用同一 cu(prefill 下即 context.cu_seqlens_q),
# 保证 base_scores 行与 Triton 分段一致;勿与 cu_seqlens_k 混用。
B = cu_seqlens.numel() - 1
G = Hq // Hk
k_lengths = cu_seqlens[1:] - cu_seqlens[:-1]
btr = compression_ctx.batch_tokens_to_retain
assert btr is not None and btr.numel() == B
btr = btr.to(device=device, dtype=torch.int32)
epsilon = compression_ctx.critical_ada_epsilon
first_stage_ratio = compression_ctx.critical_ada_first_stage_ratio
alpha_safeguard = float(compression_ctx.critical_ada_alpha_safeguard)
alpha_safeguard = max(0.0, min(1.0, alpha_safeguard))
if wo_weight.dim() == 2:
hidden_size, _ = wo_weight.shape
wo = wo_weight.transpose(0, 1).view(Hq, D, hidden_size).contiguous()
else:
wo = wo_weight.contiguous()
hidden_size = wo.size(-1)
wo_v_norm = torch.empty((N_k, Hk), dtype=torch.float32, device=device)
if B > 0 and int(k_lengths.max().item()) > 0:
if _USE_WO_L1_REFERENCE_BACKEND:
for b in range(B):
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
if k_end <= k_beg:
continue
v_seg = v[k_beg:k_end, :, :].contiguous()
wo_v_norm[k_beg:k_end, :] = _vwl1_norm_kvpress_reference(
v_seg, wo, Hk, G
)
else:
def grid_wo(META):
max_k_len = int(k_lengths.max().item())
return (B, Hk, triton.cdiv(max_k_len, META["BLOCK_K"]))
_compute_wo_v_l1_kernel[grid_wo](
v,
wo,
cu_seqlens,
wo_v_norm,
*v.stride(),
*wo.stride(),
*wo_v_norm.stride(),
Hk=Hk,
Hq=Hq,
D=D,
HIDDEN=hidden_size,
QUERY_GROUP_SIZE=G,
)
# kvpress 用 finfo.max 抬高分数;与 inf 混用时 topk 行为一致
_score_max = float(torch.finfo(torch.float32).max)
final_scores = torch.empty((N_k, Hk), dtype=torch.float32, device=device)
head_budgets_by_batch: list[Optional[torch.Tensor]] = []
for b in range(B):
k_len = int(k_lengths[b].item())
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
if k_len == 0:
head_budgets_by_batch.append(None)
continue
scores_seg = base_scores[k_beg:k_end, :].float()
keep_pairs = int(btr[b].item())
n_kept_tokens = max(1, keep_pairs // Hk)
n_kept_tokens = min(n_kept_tokens, k_len)
# scores_work: 布局 [k_len, Hk],对应 kvpress [bsz=1, H, k_len] 的 transpose(0,2) 视角下沿 token 维的 topk
scores_work = scores_seg.clone()
# --- Alpha safeguard(kvpress L148–152)---
n_safe = int(n_kept_tokens * alpha_safeguard)
nk = min(n_safe, k_len) if n_safe > 0 else 0
if nk > 0:
for hk in range(Hk):
top_idx = torch.topk(scores_work[:, hk], nk, dim=0, largest=True).indices
scores_work[top_idx, hk] = _score_max
# --- Head budgets:kvpress L158–164,展平顺序与 [bsz, H, k_len] 一致(head-major:h*K + t)---
top_pairs = min(n_kept_tokens * Hk, k_len * Hk)
if top_pairs <= 0:
head_budgets_by_batch.append(None)
wn = wo_v_norm[k_beg:k_end, :]
final_scores[k_beg:k_end, :] = (scores_seg + epsilon) * wn
continue
budget_flat = scores_work.permute(1, 0).contiguous().reshape(-1)
top_idx_flat = torch.topk(
budget_flat, top_pairs, largest=True, sorted=False
).indices
top_head_idx = top_idx_flat // k_len
head_budgets = torch.bincount(top_head_idx, minlength=Hk).to(torch.int64)
head_budgets_by_batch.append(head_budgets)
# --- Stage 1(kvpress L166–171):在已 safeguard 的 scores_work 上沿 token 维 top-k ---
head_selection_budget_1st = (
(head_budgets.to(torch.float32) * float(first_stage_ratio))
.to(torch.int64)
.tolist()
)
M1 = max(head_selection_budget_1st) if head_selection_budget_1st else 0
mk = min(M1, k_len) if M1 > 0 else 0
if mk > 0:
top_k_index = torch.topk(scores_work, mk, dim=0, largest=True, sorted=True).indices
for hk in range(Hk):
phase1_budget = int(head_selection_budget_1st[hk])
if phase1_budget <= 0:
continue
take = min(phase1_budget, mk)
scores_work[top_k_index[:take, hk], hk] = _score_max
# --- Stage 2 重加权(kvpress L173–175)---
wn = wo_v_norm[k_beg:k_end, :]
scores_fused = (scores_work + epsilon) * wn
# --- Stage 2 scatter(kvpress L176–179)---
M2 = int(head_budgets.max().item())
mk2 = min(M2, k_len) if M2 > 0 else 0
if mk2 > 0:
top_k_index2 = torch.topk(
scores_fused, mk2, dim=0, largest=True, sorted=True
).indices
for hk in range(Hk):
budget = int(head_budgets[hk].item())
if budget <= 0:
continue
take = min(budget, mk2)
scores_fused[top_k_index2[:take, hk], hk] = _score_max
final_scores[k_beg:k_end, :] = scores_fused
masked_key_indices = None
for b in range(B):
k_len = int(k_lengths[b].item())
if k_len == 0:
continue
keep_pairs = int(btr[b].item())
total_pairs = k_len * Hk
if keep_pairs >= total_pairs:
continue
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
n_prune_pairs = min(total_pairs - keep_pairs, total_pairs)
if n_prune_pairs <= 0:
continue
# kvpress L187:``scores.reshape(bsz, -1)`` 即 [H, K] 按 head-major 展平(flat = h*K + t)
flat_scores = (
final_scores[k_beg:k_end, :].permute(1, 0).contiguous().reshape(-1)
)
prune_idx = torch.topk(
-flat_scores, min(n_prune_pairs, flat_scores.numel()), sorted=False
).indices
batch_idx = torch.full_like(prune_idx, b, dtype=torch.int64)
head_idx = prune_idx // k_len
seq_idx = prune_idx % k_len + k_beg
if masked_key_indices is None:
masked_key_indices = (batch_idx, head_idx, seq_idx)
else:
masked_key_indices = (
torch.cat([masked_key_indices[0], batch_idx]),
torch.cat([masked_key_indices[1], head_idx]),
torch.cat([masked_key_indices[2], seq_idx]),
)
if store_stream is not None:
final_scores.record_stream(store_stream)
return final_scores, masked_key_indices
class CriticalAdaKVCompression(BaseCompressionMethod):
"""
仅 ``critical_ada_base_scorer == "compactor"`` 时与 kvpress ``CompactorPress.score`` 一致
(``kvpress_compactor_post_rope``:``blending * l_scores + attn_scores``);其它 base(如 SnapKV)
走对应单一 ScorerPress,再叠 CriticalAda。须由 Attention 在 post-RoPE 前注入 ``compression_context.wo_weight``。
"""
@staticmethod
def pre_rope_scoring(
q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, context
) -> Optional[torch.Tensor]:
cc = context.compression_context
base = (
getattr(cc, "critical_ada_base_scorer", "compactor")
if cc is not None
else "compactor"
)
if str(base).lower() == "compactor":
return CompactorCompression.pre_rope_scoring(q, k, v, context)
return SnapKVCompression.pre_rope_scoring(q, k, v, context)
@staticmethod
def post_rope_scoring(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
pre_rope_scores: Optional[torch.Tensor],
context,
) -> Optional[torch.Tensor]:
compression_context = context.compression_context
assert compression_context is not None
base = str(getattr(compression_context, "critical_ada_base_scorer", "compactor")).lower()
if base == "compactor":
# 特例:与 ``CompactorPress.score`` / ``CompactorCompression.post_rope_scoring`` 一致。
if context.STORE_STREAM is not None:
torch.cuda.current_stream().wait_stream(context.STORE_STREAM)
blending = resolve_kvpress_compactor_blending(compression_context)
base_scores = maybe_execute_in_stream(
kvpress_compactor_post_rope,
q,
k,
v,
context.cu_seqlens_q,
pre_rope_scores,
compression_context,
context.max_seqlen_q,
chunk_size=CompactorCompression.chunk_size,
blending=float(blending),
STORE_STREAM=context.STORE_STREAM,
)
else:
base_scores = SnapKVCompression.post_rope_scoring(
q, k, v, pre_rope_scores, context
)
wo_weight = compression_context.wo_weight
if wo_weight is None:
return base_scores
scores, _masked = maybe_execute_in_stream(
critical_ada_key_scores,
q,
k,
v,
wo_weight,
context.cu_seqlens_q,
base_scores,
compression_context,
STORE_STREAM=context.STORE_STREAM,
store_stream=context.STORE_STREAM,
)
return scores
@staticmethod
def prepare_layer(module: torch.nn.Module, device: torch.device, dtype: torch.dtype):
"""可选:预计算并缓存 Wo;实际推理以 Attention.forward 中注入的 ``cc.wo_weight`` 为准。"""
if not hasattr(module, "o_proj") or module.o_proj.weight is None:
return
if not hasattr(module, "num_heads") or not hasattr(module, "head_dim"):
return
wo_raw = module.o_proj.weight.data
hidden_size, _ = wo_raw.shape
Hq = module.num_heads
head_dim = module.head_dim
wo = (
wo_raw.transpose(0, 1)
.view(Hq, head_dim, hidden_size)
.to(device=device, dtype=torch.float32)
)
module._critical_ada_wo_weight = wo
"""
CriticalAdaKV: 在 Compactor(pre RoPE 杠杆分 + post RoPE 非因果注意力融合)基础上,
用输出投影 Wo 对 Value 的 L1 范数做 Stage-2 重加权;Stage-1 在 Compactor 基础分上做预算内 top-k 保护。
预算与 compactor_vllm 引擎一致:使用 ``compression_context.batch_tokens_to_retain``(flatten 的
(token, head) 对数量)。Stage1/2 与 kvpress 论文/实现一致;``||Wo@V||_1`` 在 **算法上** 与
``CriticalKVPress.vwl1norm`` 相同(GQA 上逐 query 头 L1 再对组取均值)。**默认用 Triton**
(``_compute_wo_v_l1_kernel``);若需与 PyTorch 逐行对齐,将模块内 ``_USE_WO_L1_REFERENCE_BACKEND`` 改为 ``True`` 即走 ``_vwl1_norm_kvpress_reference``。
注意:不得在 import 时加载 ``compactor_vllm.utils.context``(其会再 import ``CompressionMethod``,
与 ``compression/__init__.py`` 导入本模块形成环)。运行时只使用与 ``CompressionContext`` 同字段的 duck 对象。
"""
from __future__ import annotations
from typing import Any, Optional, Tuple
import torch
import triton
from triton import language as tl
from transformers.models.llama.modeling_llama import repeat_kv
from compactor_vllm.compression.common import BaseCompressionMethod
from compactor_vllm.compression.compactor import (
CompactorCompression,
non_causal_attn_scores,
)
from compactor_vllm.compression.snapkv import SnapKVCompression
from compactor_vllm.utils.helpers import maybe_execute_in_stream
from compactor_vllm.utils.triton_compat import autotune as triton_autotune
# Wo@V 的 L1:False = Triton(默认),True = PyTorch 参考(调试/对齐)
_USE_WO_L1_REFERENCE_BACKEND = False
def _vwl1_norm_kvpress_reference(
values_seg: torch.Tensor,
wo: torch.Tensor,
num_kv_heads: int,
num_query_groups: int,
) -> torch.Tensor:
"""
与 kvpress ``CriticalKVPress.vwl1norm`` 等价的 **可选参考实现**(PyTorch,仅用于核对;
将 ``_USE_WO_L1_REFERENCE_BACKEND`` 置为 ``True`` 时选用,默认走 Triton)。
算法:repeat_kv → 逐 query 头 ``|V @ Wo_h|_1`` → 在 GQA 组上 mean,与 Triton 路径同一公式。
"""
k_len, Hk, D = values_seg.shape
Hq, D_wo, hidden = wo.shape
assert D == D_wo and Hk == num_kv_heads and Hq == Hk * num_query_groups
# [1, Hk, k_len, D] 与 HF repeat_kv 约定一致
v_4d = values_seg.permute(1, 0, 2).unsqueeze(0).contiguous()
v_rep = repeat_kv(v_4d, num_query_groups) # [1, Hq, k_len, D]
# Wo 在 attention 里注入为 float32,V 常为 bf16/fp16,matmul 前对齐 dtype
wo_f = wo
head_list = []
for head in range(Hq):
v_h = v_rep[0, head, :, :].to(dtype=wo_f.dtype)
head_wov = v_h.matmul(wo_f[head, :, :])
head_wov_norm = torch.norm(head_wov, p=1, dim=-1)
head_list.append(head_wov_norm)
stacked = torch.stack(head_list, dim=0) # [Hq, k_len]
stacked = stacked.view(Hk, num_query_groups, k_len).mean(dim=1)
return stacked.transpose(0, 1).contiguous()
# ============================================================================
# Triton:||Wo @ V||₁ 按 kvpress 定义(GQA 上对 query 组 L1 后取均值)
# ============================================================================
@triton_autotune(
configs=[
triton.Config({"BLOCK_K": bk, "BLOCK_D": bd}, num_warps=nw, num_stages=ns)
for bk in [32, 64, 128]
for bd in [32, 64]
for nw in [4, 8]
for ns in [3, 4]
],
key=["Hk", "D", "HIDDEN"],
cache_results=True,
)
@triton.jit
def _compute_wo_v_l1_kernel(
V,
WO,
cu_k,
OUT,
STRIDE_V_NK,
STRIDE_V_HK,
STRIDE_V_D,
STRIDE_WO_HQ,
STRIDE_WO_D,
STRIDE_WO_HID,
STRIDE_OUT_NK,
STRIDE_OUT_HK,
Hk: tl.constexpr,
Hq: tl.constexpr,
D: tl.constexpr,
HIDDEN: tl.constexpr,
QUERY_GROUP_SIZE: tl.constexpr,
BLOCK_K: tl.constexpr,
BLOCK_D: tl.constexpr,
):
"""对每个 KV 头:对 G 个 query 头分别算 ``sum(|V @ Wo|)``,再除以 G(与 kvpress mean 一致)。"""
b = tl.program_id(0)
hk = tl.program_id(1)
ks = tl.program_id(2)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
nk_off = ks * BLOCK_K + tl.arange(0, BLOCK_K)
nk = k_beg + nk_off
k_mask = nk < k_end
out_ptrs = OUT + nk * STRIDE_OUT_NK + hk * STRIDE_OUT_HK
l1_sum = tl.zeros([BLOCK_K], dtype=tl.float32)
for g in range(QUERY_GROUP_SIZE):
hq = hk * QUERY_GROUP_SIZE + g
v_ptrs = (
V
+ nk[:, None] * STRIDE_V_NK
+ hk * STRIDE_V_HK
+ tl.arange(0, D)[None, :] * STRIDE_V_D
)
v_blk = tl.load(v_ptrs, mask=k_mask[:, None], other=0.0).to(tl.float32)
for hid_off in range(0, HIDDEN, BLOCK_D):
hid_idx = hid_off + tl.arange(0, BLOCK_D)
hid_mask = hid_idx < HIDDEN
wo_ptrs = (
WO
+ hq * STRIDE_WO_HQ
+ tl.arange(0, D)[:, None] * STRIDE_WO_D
+ hid_idx[None, :] * STRIDE_WO_HID
)
wo_tile = tl.load(wo_ptrs, mask=hid_mask[None, :], other=0.0).to(tl.float32)
wov_tile = tl.dot(v_blk, wo_tile)
l1_sum += tl.sum(tl.abs(wov_tile), axis=1)
l1_sum = l1_sum / QUERY_GROUP_SIZE
tl.store(out_ptrs, l1_sum, mask=k_mask)
# ============================================================================
# Triton:Stage 1 保护 + Stage 2 加权融合(逐元素)
# ============================================================================
@triton_autotune(
configs=[triton.Config({"BLOCK_K": bk}) for bk in [32, 64, 128, 256]],
key=["Hk"],
cache_results=True,
)
@triton.jit
def _critical_ada_fuse_kernel(
BASE_SCORES,
WO_V_NORM,
STAGE1_MASK,
cu_k,
OUT,
STRIDE_BS_NK,
STRIDE_BS_HK,
STRIDE_WN_NK,
STRIDE_WN_HK,
STRIDE_S1_NK,
STRIDE_S1_HK,
STRIDE_OUT_NK,
STRIDE_OUT_HK,
EPSILON: tl.constexpr,
Hk: tl.constexpr,
BLOCK_K: tl.constexpr,
):
b = tl.program_id(0)
hk = tl.program_id(1)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
for ks in tl.range(k_beg, k_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_end
bs_ptrs = BASE_SCORES + nk * STRIDE_BS_NK + hk * STRIDE_BS_HK
wn_ptrs = WO_V_NORM + nk * STRIDE_WN_NK + hk * STRIDE_WN_HK
s1_ptrs = STAGE1_MASK + nk * STRIDE_S1_NK + hk * STRIDE_S1_HK
base = tl.load(bs_ptrs, mask=kmask, other=0.0)
wnorm = tl.load(wn_ptrs, mask=kmask, other=1.0)
stage1_protect = tl.load(s1_ptrs, mask=kmask, other=0).to(tl.int32)
fused = (base + EPSILON) * wnorm
fused = tl.where(stage1_protect == 1, float("inf"), fused)
out_ptrs = OUT + nk * STRIDE_OUT_NK + hk * STRIDE_OUT_HK
tl.store(out_ptrs, fused, mask=kmask)
def critical_ada_key_scores(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
wo_weight: torch.Tensor,
cu_seqlens: torch.Tensor,
base_scores: torch.Tensor,
compression_ctx: Any,
*,
store_stream: Optional[torch.cuda.Stream] = None,
) -> Tuple[torch.Tensor, Optional[Tuple[torch.Tensor, torch.Tensor, torch.Tensor]]]:
"""
使用与引擎一致的保留预算 ``batch_tokens_to_retain``(每条序列的 (token, head) 对数),
在每条序列上对齐 kvpress ``CriticalAdaKVPress.compress``(整段 ``k_len``、与源实现相同的
top-k / scatter 顺序);仅 base 分数来自 compactor_vllm 的 Compactor/SnapKV。
Args:
compression_ctx: 与 ``CompressionContext`` 相同字段即可(duck typing),须含
``batch_tokens_to_retain``;可选 ``critical_ada_epsilon``、
``critical_ada_first_stage_ratio``、``critical_ada_alpha_safeguard``。
"""
assert q.stride(-1) == 1 and k.stride(-1) == 1 and v.stride(-1) == 1
device = q.device
_, Hq, D = q.shape
N_k, Hk, Dk = k.shape
assert D == Dk and Hq % Hk == 0
# 与 non_causal_attn_scores 使用同一 cu(prefill 下即 context.cu_seqlens_q),
# 保证 base_scores 行与 Triton 分段一致;勿与 cu_seqlens_k 混用。
B = cu_seqlens.numel() - 1
G = Hq // Hk
k_lengths = cu_seqlens[1:] - cu_seqlens[:-1]
btr = compression_ctx.batch_tokens_to_retain
assert btr is not None and btr.numel() == B
btr = btr.to(device=device, dtype=torch.int32)
epsilon = compression_ctx.critical_ada_epsilon
first_stage_ratio = compression_ctx.critical_ada_first_stage_ratio
alpha_safeguard = float(compression_ctx.critical_ada_alpha_safeguard)
alpha_safeguard = max(0.0, min(1.0, alpha_safeguard))
if wo_weight.dim() == 2:
hidden_size, _ = wo_weight.shape
wo = wo_weight.transpose(0, 1).view(Hq, D, hidden_size).contiguous()
else:
wo = wo_weight.contiguous()
hidden_size = wo.size(-1)
wo_v_norm = torch.empty((N_k, Hk), dtype=torch.float32, device=device)
if B > 0 and int(k_lengths.max().item()) > 0:
if _USE_WO_L1_REFERENCE_BACKEND:
for b in range(B):
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
if k_end <= k_beg:
continue
v_seg = v[k_beg:k_end, :, :].contiguous()
wo_v_norm[k_beg:k_end, :] = _vwl1_norm_kvpress_reference(
v_seg, wo, Hk, G
)
else:
def grid_wo(META):
max_k_len = int(k_lengths.max().item())
return (B, Hk, triton.cdiv(max_k_len, META["BLOCK_K"]))
_compute_wo_v_l1_kernel[grid_wo](
v,
wo,
cu_seqlens,
wo_v_norm,
*v.stride(),
*wo.stride(),
*wo_v_norm.stride(),
Hk=Hk,
Hq=Hq,
D=D,
HIDDEN=hidden_size,
QUERY_GROUP_SIZE=G,
)
stage1_mask = torch.zeros((N_k, Hk), dtype=torch.int32, device=device)
head_budgets_by_batch: list[Optional[torch.Tensor]] = []
for b in range(B):
k_len = int(k_lengths[b].item())
if k_len == 0:
head_budgets_by_batch.append(None)
continue
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
keep_pairs = int(btr[b].item())
scores_seg = base_scores[k_beg:k_end, :]
# 与 kvpress 的 n_kept 一致:每头保留 n_kept 个 token
n_kept_tokens = max(1, keep_pairs // Hk)
n_kept_tokens = min(n_kept_tokens, k_len)
# kvpress:topk 在「未改动的」scores 上取索引,scatter 只写在副本上,供 head_budgets 用;
# Stage1 仍用原始 scores_seg(见下)。
working = scores_seg.clone()
n_safe = int(n_kept_tokens * alpha_safeguard)
if n_safe > 0:
nk = min(n_safe, k_len)
for hk in range(Hk):
top_idx = torch.topk(scores_seg[:, hk], nk, sorted=True).indices
working[:, hk].scatter_(0, top_idx, float("inf"))
top_pairs = min(n_kept_tokens * Hk, working.numel())
if top_pairs <= 0:
head_budgets_by_batch.append(None)
continue
top_idx_flat = torch.topk(working.reshape(-1), top_pairs, sorted=False).indices
top_head_idx = top_idx_flat % Hk
head_budgets = torch.bincount(top_head_idx, minlength=Hk).to(torch.int32)
head_budgets_by_batch.append(head_budgets)
# Stage 1:与 kvpress 相同 — 先 topk(..., M1, sorted=True),再每头取前 phase1 个下标
head_selection_budget_1st = (
(head_budgets.to(torch.float32) * float(first_stage_ratio))
.to(torch.int64)
.tolist()
)
M1 = max(head_selection_budget_1st) if head_selection_budget_1st else 0
if M1 > 0:
mk = min(M1, k_len)
for hk in range(Hk):
phase1_budget = int(head_selection_budget_1st[hk])
if phase1_budget <= 0:
continue
full_idx = torch.topk(scores_seg[:, hk], mk, sorted=True).indices
take = min(phase1_budget, mk)
stage1_mask[k_beg + full_idx[:take], hk] = 1
final_scores = torch.empty((N_k, Hk), dtype=torch.float32, device=device)
def grid_fuse(_META):
return (B, Hk)
_critical_ada_fuse_kernel[grid_fuse](
base_scores,
wo_v_norm,
stage1_mask,
cu_seqlens,
final_scores,
*base_scores.stride(),
*wo_v_norm.stride(),
*stage1_mask.stride(),
*final_scores.stride(),
Hk=Hk,
EPSILON=float(epsilon),
)
# Stage 2(kvpress):对融合后分数先 topk(..., M2, sorted=True),再每头取前 budget 个下标置 inf
for b in range(B):
hb = head_budgets_by_batch[b]
if hb is None:
continue
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
k_len = k_end - k_beg
if k_len <= 0:
continue
fused_seg = final_scores[k_beg:k_end, :]
M2 = int(hb.max().item())
if M2 <= 0:
continue
mk = min(M2, k_len)
for hk in range(Hk):
budget = int(hb[hk].item())
if budget <= 0:
continue
full_idx = torch.topk(fused_seg[:, hk], mk, sorted=True).indices
take = min(budget, mk)
final_scores[k_beg + full_idx[:take], hk] = float("inf")
masked_key_indices = None
for b in range(B):
k_len = int(k_lengths[b].item())
if k_len == 0:
continue
keep_pairs = int(btr[b].item())
total_pairs = k_len * Hk
if keep_pairs >= total_pairs:
continue
k_beg = int(cu_seqlens[b].item())
k_end = int(cu_seqlens[b + 1].item())
n_prune_pairs = min(total_pairs - keep_pairs, total_pairs)
if n_prune_pairs <= 0:
continue
flat_scores = final_scores[k_beg:k_end, :].reshape(-1)
prune_idx = torch.topk(
-flat_scores, min(n_prune_pairs, flat_scores.numel()), sorted=False
).indices
batch_idx = torch.full_like(prune_idx, b, dtype=torch.int64)
head_idx = prune_idx % Hk
seq_idx = prune_idx // Hk + k_beg
if masked_key_indices is None:
masked_key_indices = (batch_idx, head_idx, seq_idx)
else:
masked_key_indices = (
torch.cat([masked_key_indices[0], batch_idx]),
torch.cat([masked_key_indices[1], head_idx]),
torch.cat([masked_key_indices[2], seq_idx]),
)
if store_stream is not None:
final_scores.record_stream(store_stream)
return final_scores, masked_key_indices
class CriticalAdaKVCompression(BaseCompressionMethod):
"""
以 CompactorCompression 为基分(pre RoPE 杠杆 + post RoPE 非因果融合),
再应用 CriticalAda 两阶段加权;须由 Attention 在 post-RoPE 前注入 ``compression_context.wo_weight``。
"""
@staticmethod
def pre_rope_scoring(
q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, context
) -> Optional[torch.Tensor]:
cc = context.compression_context
base = getattr(cc, "critical_ada_base_scorer", "snapkv") if cc is not None else "compactor"
if str(base).lower() == "snapkv":
return SnapKVCompression.pre_rope_scoring(q, k, v, context)
return CompactorCompression.pre_rope_scoring(q, k, v, context)
@staticmethod
def post_rope_scoring(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
pre_rope_scores: Optional[torch.Tensor],
context,
) -> Optional[torch.Tensor]:
compression_context = context.compression_context
assert compression_context is not None
base = str(getattr(compression_context, "critical_ada_base_scorer", "compactor")).lower()
if base == "snapkv":
base_scores = SnapKVCompression.post_rope_scoring(q, k, v, pre_rope_scores, context)
else:
# 与 compactor.py 中 CompactorCompression.post_rope_scoring 逐字一致:
# maybe_execute_in_stream(non_causal_attn_scores, q,k,v, cu_seqlens_q, max_seqlen_q, ...)
# 不得改为其它封装,否则与单独使用 COMPACTOR 时分数字不一致。
if context.STORE_STREAM is not None:
torch.cuda.current_stream().wait_stream(context.STORE_STREAM)
base_scores = maybe_execute_in_stream(
non_causal_attn_scores,
q,
k,
v,
context.cu_seqlens_q,
context.max_seqlen_q,
chunk_size=CompactorCompression.chunk_size,
sm_scale=1.0,
normalize=True,
accum_scores=pre_rope_scores,
context_lens=compression_context.context_lens,
protected_first_tokens=compression_context.protected_first_tokens,
protected_last_tokens=compression_context.protected_last_tokens,
accum_blending=0.5,
)
wo_weight = compression_context.wo_weight
if wo_weight is None:
return base_scores
scores, _masked = maybe_execute_in_stream(
critical_ada_key_scores,
q,
k,
v,
wo_weight,
context.cu_seqlens_q,
base_scores,
compression_context,
STORE_STREAM=context.STORE_STREAM,
store_stream=context.STORE_STREAM,
)
return scores
@staticmethod
def prepare_layer(module: torch.nn.Module, device: torch.device, dtype: torch.dtype):
"""可选:预计算并缓存 Wo;实际推理以 Attention.forward 中注入的 ``cc.wo_weight`` 为准。"""
if not hasattr(module, "o_proj") or module.o_proj.weight is None:
return
if not hasattr(module, "num_heads") or not hasattr(module, "head_dim"):
return
wo_raw = module.o_proj.weight.data
hidden_size, _ = wo_raw.shape
Hq = module.num_heads
head_dim = module.head_dim
wo = (
wo_raw.transpose(0, 1)
.view(Hq, head_dim, hidden_size)
.to(device=device, dtype=torch.float32)
)
module._critical_ada_wo_weight = wo
import math
from typing import Optional
import torch
import triton
from triton import language as tl
from compactor_vllm.compression.common import BaseCompressionMethod
from compactor_vllm.utils.helpers import maybe_execute_in_stream
from compactor_vllm.utils.triton_compat import autotune as triton_autotune
# SnapKV defaults aligned with kvpress `SnapKVPress` (snapkv_press.py).
DEFAULT_SNAPKV_WINDOW_SIZE = 64
DEFAULT_SNAPKV_KERNEL_SIZE = 5
class SnapKVCompression(BaseCompressionMethod):
@staticmethod
def pre_rope_scoring(
q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, context
) -> Optional[torch.Tensor]:
return None
@staticmethod
def post_rope_scoring(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
pre_rope_scores: torch.Tensor,
context,
) -> Optional[torch.Tensor]:
scores = maybe_execute_in_stream(
query_aware_key_scores,
q,
k,
context.cu_seqlens_q,
context.cu_seqlens_k,
w=DEFAULT_SNAPKV_WINDOW_SIZE,
kernel_size=DEFAULT_SNAPKV_KERNEL_SIZE,
STORE_STREAM=context.STORE_STREAM,
)
return scores
@triton_autotune(
configs=[
triton.Config(
{"BLOCK_Q": bq, "BLOCK_K": bk}, num_warps=num_warps, num_stages=num_stages
)
for bq in [32, 64]
for bk in [32, 64]
for num_warps in [4, 8]
for num_stages in [3, 4]
],
key=["QUERY_GROUP_SIZE", "D", "ROWS_MAX"],
cache_results=True,
)
@triton.jit
def _lse_and_store_logits_kernel(
Q,
K,
cu_q,
cu_k,
w_b, # int32 pointers
out_m,
out_S, # [B, Hk, ROWS_MAX] float32
LOGITS, # [Nk, Hk, ROWS_MAX] float32
sm_scale, # float
QUERY_GROUP_SIZE: tl.constexpr,
D: tl.constexpr,
STRIDE_Q_NQ,
STRIDE_Q_HQ,
STRIDE_K_NK,
STRIDE_K_HK,
STRIDE_M_B,
STRIDE_M_H,
STRIDE_M_R,
STRIDE_S_B,
STRIDE_S_H,
STRIDE_S_R,
STRIDE_LG_NK,
STRIDE_LG_HK,
STRIDE_LG_R,
BLOCK_Q: tl.constexpr,
BLOCK_K: tl.constexpr,
ROWS_MAX,
):
# program ids
b = tl.program_id(0)
hk = tl.program_id(1)
rid = tl.program_id(2) # row-tile id
# batch segment bounds
q_end = tl.load(cu_q + b + 1)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
win = tl.load(w_b + b)
q_win_beg = q_end - win
k_eff_end = k_end - win
if (win <= 0) or (k_eff_end <= k_beg):
return
# rows for this (b,hk)
rows_b = win * QUERY_GROUP_SIZE
row0 = rid * BLOCK_Q
if row0 >= rows_b:
return
# exp(x) = exp2(x * 1/ln2)
qk_scale = sm_scale * 1.4426950408889634
offs_qrow = row0 + tl.arange(0, BLOCK_Q)
row_mask = offs_qrow < rows_b
# map row -> (q_idx, hq_local)
hq_local = offs_qrow % QUERY_GROUP_SIZE
q_off = offs_qrow // QUERY_GROUP_SIZE
q_idx = q_win_beg + q_off
hq_glob = hk * QUERY_GROUP_SIZE + hq_local
offs_d = tl.arange(0, D)
q_ptrs = (
Q
+ q_idx[:, None] * STRIDE_Q_NQ
+ hq_glob[:, None] * STRIDE_Q_HQ
+ offs_d[None, :]
)
q_rows = tl.load(q_ptrs, mask=row_mask[:, None], other=0.0)
m = tl.zeros([BLOCK_Q], dtype=tl.float32) + (-float("inf"))
S = tl.zeros([BLOCK_Q], dtype=tl.float32)
# Full-sequence causal attention (matches kvpress softmax), then use prefix columns only.
for ks in tl.range(k_beg, k_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_end
k_ptrs = K + nk[:, None] * STRIDE_K_NK + hk * STRIDE_K_HK + offs_d[None, :]
k_blk = tl.load(k_ptrs, mask=kmask[:, None], other=0.0) # [BK, D]
s = tl.dot(q_rows, k_blk.T) * qk_scale # [BQ, BK]
s = tl.where(kmask[None, :], s, -float("inf"))
# Causal: key j only if j <= q_idx (same as kvpress triu mask on the window×k_len grid).
causal_ok = nk[None, :] <= q_idx[:, None]
s = tl.where(causal_ok, s, -float("inf"))
# store prefix logits only (for marginal probs on prefix keys)
log_ptrs = (
LOGITS
+ nk[:, None] * STRIDE_LG_NK
+ hk * STRIDE_LG_HK
+ (row0 + tl.arange(0, BLOCK_Q))[None, :] * STRIDE_LG_R
)
store_mask = kmask & (nk < k_eff_end)
tl.store(log_ptrs, s.T, mask=store_mask[:, None] & row_mask[None, :])
# log2 streaming LSE over all keys in [k_beg, k_end) (after causal mask)
cur_max = tl.max(s, 1) # [BQ]
n_m = tl.maximum(m, cur_max)
rescale = tl.math.exp2(m - n_m)
S = S * rescale + tl.sum(tl.math.exp2(s - n_m[:, None]), 1)
m = n_m
# store m,S for these rows
m_base = out_m + b * STRIDE_M_B + hk * STRIDE_M_H + row0 * STRIDE_M_R
S_base = out_S + b * STRIDE_S_B + hk * STRIDE_S_H + row0 * STRIDE_S_R
tl.store(m_base + tl.arange(0, BLOCK_Q) * STRIDE_M_R, m, mask=row_mask)
tl.store(S_base + tl.arange(0, BLOCK_Q) * STRIDE_S_R, S, mask=row_mask)
@triton_autotune(
configs=[
triton.Config({"BLOCK_Q": bq, "BLOCK_K": bk})
for bq in [16, 32, 64]
for bk in [32, 64, 128]
],
key=["HK", "HQ"],
cache_results=True,
)
@triton.jit
def _prefix_probs_kernel(
cu_k,
w_b,
in_m,
in_S, # [B, Hk, ROWS_MAX] f32
LOGITS, # [Nk, Hk, ROWS_MAX] f32, base-2 logits (prefix keys only)
PROBS, # [Nk, Hk, ROWS_MAX] f32 — per-row prefix marginal probs
#
QUERY_GROUP_SIZE: tl.constexpr,
STRIDE_M_B,
STRIDE_M_H,
STRIDE_M_R,
STRIDE_S_B,
STRIDE_S_H,
STRIDE_S_R,
STRIDE_LG_NK,
STRIDE_LG_HK,
STRIDE_LG_R,
STRIDE_PB_NK,
STRIDE_PB_HK,
STRIDE_PB_R,
BLOCK_Q: tl.constexpr,
BLOCK_K: tl.constexpr,
):
b = tl.program_id(0)
hk = tl.program_id(1)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
win = tl.load(w_b + b)
k_eff_end = k_end - win
if (win <= 0) or (k_eff_end <= k_beg):
return
rows_b = win * QUERY_GROUP_SIZE
for ks in tl.range(k_beg, k_eff_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_eff_end
for row0 in tl.range(0, rows_b, BLOCK_Q):
r_idx = row0 + tl.arange(0, BLOCK_Q)
rmask = r_idx < rows_b
m_ptr = in_m + b * STRIDE_M_B + hk * STRIDE_M_H + row0 * STRIDE_M_R
S_ptr = in_S + b * STRIDE_S_B + hk * STRIDE_S_H + row0 * STRIDE_S_R
m = tl.load(
m_ptr + tl.arange(0, BLOCK_Q) * STRIDE_M_R,
mask=rmask,
other=-float("inf"),
)
S = tl.load(
S_ptr + tl.arange(0, BLOCK_Q) * STRIDE_S_R, mask=rmask, other=0.0
)
valid_row = S > 0
m = tl.where(valid_row, m, 0.0)
S = tl.where(valid_row, S, 1.0)
log_ptrs = (
LOGITS
+ nk[:, None] * STRIDE_LG_NK
+ hk * STRIDE_LG_HK
+ (row0 + tl.arange(0, BLOCK_Q))[None, :] * STRIDE_LG_R
)
s_T = tl.load(
log_ptrs, mask=kmask[:, None] & rmask[None, :], other=-float("inf")
) # [BK, BQ]
probs_T = tl.math.exp2(s_T - m[None, :]) / S[None, :]
probs_T = tl.where(valid_row[None, :], probs_T, 0.0)
prob_ptrs = (
PROBS
+ nk[:, None] * STRIDE_PB_NK
+ hk * STRIDE_PB_HK
+ (row0 + tl.arange(0, BLOCK_Q))[None, :] * STRIDE_PB_R
)
tl.store(prob_ptrs, probs_T, mask=kmask[:, None] & rmask[None, :])
@triton_autotune(
configs=[triton.Config({"BLOCK_K": bk}) for bk in [32, 64, 128]],
key=["HK"],
cache_results=True,
)
@triton.jit
def _zscore_per_batch_epilogue(
OUT, # [Nk, Hk], float32
cu_k,
w_b, # [B+1], [B] int32
STRIDE_OUT_NK,
STRIDE_OUT_HK,
HK: tl.constexpr, # Hk
EPS: tl.constexpr, # e.g., 1e-12
BLOCK_K: tl.constexpr, # e.g., 128
):
b = tl.program_id(0)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
win = tl.load(w_b + b)
k_eff_end = k_end - win
if k_eff_end <= k_beg:
return
sumv = tl.zeros([], dtype=tl.float32)
sumsq = tl.zeros([], dtype=tl.float32)
count = ((k_eff_end - k_beg) * HK).to(tl.float32)
for ks in tl.range(k_beg, k_eff_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_eff_end
for h in tl.range(0, HK):
ptrs = OUT + nk * STRIDE_OUT_NK + h * STRIDE_OUT_HK
vals = tl.load(ptrs, mask=kmask, other=0.0).to(tl.float32)
sumv += tl.sum(vals, 0)
sumsq += tl.sum(vals * vals, 0)
mean = sumv / count
var = tl.maximum(sumsq / count - mean * mean, 0.0)
invstd = 1.0 / tl.sqrt(var + EPS)
for ks in tl.range(k_beg, k_eff_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_eff_end
for h in tl.range(0, HK):
ptrs = OUT + nk * STRIDE_OUT_NK + h * STRIDE_OUT_HK
vals = tl.load(ptrs, mask=kmask, other=0.0).to(tl.float32)
vals = (vals - mean) * invstd
tl.store(ptrs, vals, mask=kmask)
@triton_autotune(
configs=[triton.Config({"BLOCK_T": bt}) for bt in [32, 64, 128, 256]],
key=["KERNEL_SIZE"],
cache_results=True,
)
@triton.jit
def _snapkv_avg_pool1d_kernel(
IN,
OUT,
Lp,
STRIDE_IN_C,
STRIDE_IN_L,
STRIDE_OUT_C,
STRIDE_OUT_L,
KERNEL_SIZE: tl.constexpr,
PAD: tl.constexpr,
BLOCK_T: tl.constexpr,
):
"""
Symmetric 1D average pool on the last dimension, matching
`F.avg_pool1d(x, kernel_size=K, padding=K//2, stride=1)` on `x` shaped [C, Lp]
(equivalent to PyTorch [C, 1, Lp] avg_pool1d with divisor = kernel size).
"""
c = tl.program_id(0)
t0 = tl.program_id(1) * BLOCK_T + tl.arange(0, BLOCK_T)
mask = t0 < Lp
acc = tl.zeros([BLOCK_T], dtype=tl.float32)
for j in tl.static_range(KERNEL_SIZE):
idx = t0 - PAD + j
valid = (idx >= 0) & (idx < Lp)
ptrs = IN + c * STRIDE_IN_C + idx * STRIDE_IN_L
v = tl.load(ptrs, mask=valid & mask, other=0.0).to(tl.float32)
acc += v
acc = acc / tl.cast(KERNEL_SIZE, tl.float32)
out_ptrs = OUT + c * STRIDE_OUT_C + t0 * STRIDE_OUT_L
tl.store(out_ptrs, acc, mask=mask)
def _snapkv_avg_pool1d_triton(x: torch.Tensor, kernel_size: int) -> torch.Tensor:
"""
kvpress-equivalent smoothing: same as `F.avg_pool1d` on [Hk*G, 1, Lp].
`x` must be float32 and contiguous along Lp (shape [Hk, G, Lp]).
"""
assert x.dtype == torch.float32
Hk, G, Lp = x.shape
if Lp == 0:
return x
pad = kernel_size // 2
x2 = x.reshape(Hk * G, Lp).contiguous()
out = torch.empty_like(x2)
C = Hk * G
si_c, si_l = x2.stride()
so_c, so_l = out.stride()
def grid(meta):
return (C, triton.cdiv(Lp, meta["BLOCK_T"]))
_snapkv_avg_pool1d_kernel[grid](
x2,
out,
Lp,
si_c,
si_l,
so_c,
so_l,
KERNEL_SIZE=kernel_size,
PAD=pad,
)
return out.view(Hk, G, Lp)
def _snapkv_kvpress_epilogue(
probs_buf: torch.Tensor,
out: torch.Tensor,
cu_seqlens_k: torch.Tensor,
w: torch.Tensor,
G: int,
Hk: int,
kernel_size: int,
) -> None:
"""
Match kvpress SnapKV order: mean over window queries → symmetric avg_pool1d
→ mean over GQA groups → pad tail with global max of prefix scores.
"""
B = cu_seqlens_k.numel() - 1
for b in range(B):
k_beg = int(cu_seqlens_k[b].item())
k_end = int(cu_seqlens_k[b + 1].item())
win = int(w[b].item())
k_eff_end = k_end - win
if win <= 0 or k_eff_end <= k_beg:
continue
Lp = k_eff_end - k_beg
rows_b = win * G
p = probs_buf[k_beg:k_eff_end, :, :rows_b]
# [Lp, Hk, win, G] — rows are (q_off, g) order per Triton row layout
x = p.view(Lp, Hk, win, G).mean(dim=2)
x = x.permute(1, 2, 0).contiguous() # [Hk, G, Lp]
x = _snapkv_avg_pool1d_triton(x, kernel_size)
x = x.mean(dim=1)
seg = x.permute(1, 0).contiguous()
out[k_beg:k_eff_end, :] = seg
pad_val = seg.max()
out[k_eff_end:k_end, :] = pad_val
def query_aware_key_scores(
q: torch.Tensor, # [N_q, Hq, D]
k: torch.Tensor, # [N_k, Hk, D]
cu_seqlens_q: torch.Tensor, # [B+1], int32
cu_seqlens_k: torch.Tensor, # [B+1], int32
w: torch.Tensor | int, # [B], int32
sm_scale: float = None, # defaults to 1/sqrt(D)
*,
kernel_size: int = DEFAULT_SNAPKV_KERNEL_SIZE,
accum_scores: torch.Tensor = None,
accum_blending: float = None,
normalize: bool = False,
) -> Optional[torch.Tensor]:
assert q.stride(-1) == 1 and k.stride(-1) == 1, "last dim must be contiguous"
device = q.device
N_q, Hq, D = q.shape
N_k, Hk, Dk = k.shape
assert (Hq % Hk) == 0, "Hq must be a multiple of Hk"
if sm_scale is None:
sm_scale = 1.0 / math.sqrt(D)
B = cu_seqlens_q.numel() - 1
assert B == cu_seqlens_k.numel() - 1
G = Hq // Hk
if type(w) is int:
max_w = w
w = torch.full((B,), fill_value=w, device=device, dtype=torch.int32)
else:
max_w = int(w.max().item())
assert w.numel() == B
ROWS_MAX = max_w * G
if ROWS_MAX == 0:
return torch.zeros((N_k, Hk), dtype=torch.float32, device=device)
out = torch.zeros((N_k, Hk), dtype=torch.float32, device=device)
m_scratch = torch.empty((B, Hk, ROWS_MAX), dtype=torch.float32, device=device)
S_scratch = torch.empty((B, Hk, ROWS_MAX), dtype=torch.float32, device=device)
logits_buf = torch.empty((N_k, Hk, ROWS_MAX), dtype=torch.float32, device=device)
probs_buf = torch.empty((N_k, Hk, ROWS_MAX), dtype=torch.float32, device=device)
# strides
STRIDE_Q_NQ, STRIDE_Q_HQ, _ = q.stride()
STRIDE_K_NK, STRIDE_K_HK, _ = k.stride()
STRIDE_M_B, STRIDE_M_H, STRIDE_M_R = m_scratch.stride()
STRIDE_S_B, STRIDE_S_H, STRIDE_S_R = S_scratch.stride()
STRIDE_LG_NK, STRIDE_LG_HK, STRIDE_LG_R = logits_buf.stride()
STRIDE_PB_NK, STRIDE_PB_HK, STRIDE_PB_R = probs_buf.stride()
STRIDE_OUT_NK, STRIDE_OUT_HK = out.stride()
def grid(META):
return B, Hk, triton.cdiv(ROWS_MAX, META["BLOCK_Q"])
_lse_and_store_logits_kernel[grid](
q,
k,
cu_seqlens_q,
cu_seqlens_k,
w,
m_scratch,
S_scratch,
logits_buf,
sm_scale,
QUERY_GROUP_SIZE=Hq // Hk,
D=D,
STRIDE_Q_NQ=STRIDE_Q_NQ,
STRIDE_Q_HQ=STRIDE_Q_HQ,
STRIDE_K_NK=STRIDE_K_NK,
STRIDE_K_HK=STRIDE_K_HK,
STRIDE_M_B=STRIDE_M_B,
STRIDE_M_H=STRIDE_M_H,
STRIDE_M_R=STRIDE_M_R,
STRIDE_S_B=STRIDE_S_B,
STRIDE_S_H=STRIDE_S_H,
STRIDE_S_R=STRIDE_S_R,
STRIDE_LG_NK=STRIDE_LG_NK,
STRIDE_LG_HK=STRIDE_LG_HK,
STRIDE_LG_R=STRIDE_LG_R,
ROWS_MAX=ROWS_MAX,
)
_prefix_probs_kernel[(B, Hk)](
cu_seqlens_k,
w,
m_scratch,
S_scratch,
logits_buf,
probs_buf,
QUERY_GROUP_SIZE=Hq // Hk,
STRIDE_M_B=STRIDE_M_B,
STRIDE_M_H=STRIDE_M_H,
STRIDE_M_R=STRIDE_M_R,
STRIDE_S_B=STRIDE_S_B,
STRIDE_S_H=STRIDE_S_H,
STRIDE_S_R=STRIDE_S_R,
STRIDE_LG_NK=STRIDE_LG_NK,
STRIDE_LG_HK=STRIDE_LG_HK,
STRIDE_LG_R=STRIDE_LG_R,
STRIDE_PB_NK=STRIDE_PB_NK,
STRIDE_PB_HK=STRIDE_PB_HK,
STRIDE_PB_R=STRIDE_PB_R,
)
_snapkv_kvpress_epilogue(
probs_buf, out, cu_seqlens_k, w, G, Hk, kernel_size
)
if normalize:
_zscore_per_batch_epilogue[(B,)](
out,
cu_seqlens_k,
w,
STRIDE_OUT_NK,
STRIDE_OUT_HK,
HK=Hk,
EPS=1e-12,
)
if accum_scores is not None:
if accum_blending is not None:
accum_scores.mul_(accum_blending)
accum_scores.add_(out)
return accum_scores
else:
return out
import math
from typing import Optional
import torch
import triton
from triton import language as tl
from compactor_vllm.compression.common import BaseCompressionMethod
from compactor_vllm.utils.helpers import maybe_execute_in_stream
from compactor_vllm.utils.triton_compat import autotune as triton_autotune
class SnapKVCompression(BaseCompressionMethod):
@staticmethod
def pre_rope_scoring(
q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, context
) -> Optional[torch.Tensor]:
return None
@staticmethod
def post_rope_scoring(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
pre_rope_scores: torch.Tensor,
context,
) -> Optional[torch.Tensor]:
scores = maybe_execute_in_stream(
query_aware_key_scores,
q,
k,
context.cu_seqlens_q,
context.cu_seqlens_k,
w=32,
STORE_STREAM=context.STORE_STREAM,
)
return scores
@triton_autotune(
configs=[
triton.Config(
{"BLOCK_Q": bq, "BLOCK_K": bk}, num_warps=num_warps, num_stages=num_stages
)
for bq in [32, 64]
for bk in [32, 64]
for num_warps in [4, 8]
for num_stages in [3, 4]
],
key=["QUERY_GROUP_SIZE", "D", "ROWS_MAX"],
cache_results=True,
)
@triton.jit
def _lse_and_store_logits_kernel(
Q,
K,
cu_q,
cu_k,
w_b, # int32 pointers
out_m,
out_S, # [B, Hk, ROWS_MAX] float32
LOGITS, # [Nk, Hk, ROWS_MAX] float32
sm_scale, # float
QUERY_GROUP_SIZE: tl.constexpr,
D: tl.constexpr,
STRIDE_Q_NQ,
STRIDE_Q_HQ,
STRIDE_K_NK,
STRIDE_K_HK,
STRIDE_M_B,
STRIDE_M_H,
STRIDE_M_R,
STRIDE_S_B,
STRIDE_S_H,
STRIDE_S_R,
STRIDE_LG_NK,
STRIDE_LG_HK,
STRIDE_LG_R,
BLOCK_Q: tl.constexpr,
BLOCK_K: tl.constexpr,
ROWS_MAX,
):
# program ids
b = tl.program_id(0)
hk = tl.program_id(1)
rid = tl.program_id(2) # row-tile id
# batch segment bounds
q_end = tl.load(cu_q + b + 1)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
win = tl.load(w_b + b)
q_win_beg = q_end - win
k_eff_end = k_end - win
if (win <= 0) or (k_eff_end <= k_beg):
return
# rows for this (b,hk)
rows_b = win * QUERY_GROUP_SIZE
row0 = rid * BLOCK_Q
if row0 >= rows_b:
return
# exp(x) = exp2(x * 1/ln2)
qk_scale = sm_scale * 1.4426950408889634
offs_qrow = row0 + tl.arange(0, BLOCK_Q)
row_mask = offs_qrow < rows_b
# map row -> (q_idx, hq_local)
hq_local = offs_qrow % QUERY_GROUP_SIZE
q_off = offs_qrow // QUERY_GROUP_SIZE
q_idx = q_win_beg + q_off
hq_glob = hk * QUERY_GROUP_SIZE + hq_local
offs_d = tl.arange(0, D)
q_ptrs = (
Q
+ q_idx[:, None] * STRIDE_Q_NQ
+ hq_glob[:, None] * STRIDE_Q_HQ
+ offs_d[None, :]
)
q_rows = tl.load(q_ptrs, mask=row_mask[:, None], other=0.0)
m = tl.zeros([BLOCK_Q], dtype=tl.float32) + (-float("inf"))
S = tl.zeros([BLOCK_Q], dtype=tl.float32)
for ks in tl.range(k_beg, k_eff_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_eff_end
k_ptrs = K + nk[:, None] * STRIDE_K_NK + hk * STRIDE_K_HK + offs_d[None, :]
k_blk = tl.load(k_ptrs, mask=kmask[:, None], other=0.0) # [BK, D]
s = tl.dot(q_rows, k_blk.T) * qk_scale # [BQ, BK]
s = tl.where(kmask[None, :], s, -float("inf"))
# store into LOGITS[nk, hk, row] -> [BK, BQ]
log_ptrs = (
LOGITS
+ nk[:, None] * STRIDE_LG_NK
+ hk * STRIDE_LG_HK
+ (row0 + tl.arange(0, BLOCK_Q))[None, :] * STRIDE_LG_R
)
tl.store(log_ptrs, s.T, mask=kmask[:, None] & row_mask[None, :])
# log2 streaming LSE update
cur_max = tl.max(s, 1) # [BQ]
n_m = tl.maximum(m, cur_max)
rescale = tl.math.exp2(m - n_m)
S = S * rescale + tl.sum(tl.math.exp2(s - n_m[:, None]), 1)
m = n_m
# store m,S for these rows
m_base = out_m + b * STRIDE_M_B + hk * STRIDE_M_H + row0 * STRIDE_M_R
S_base = out_S + b * STRIDE_S_B + hk * STRIDE_S_H + row0 * STRIDE_S_R
tl.store(m_base + tl.arange(0, BLOCK_Q) * STRIDE_M_R, m, mask=row_mask)
tl.store(S_base + tl.arange(0, BLOCK_Q) * STRIDE_S_R, S, mask=row_mask)
@triton_autotune(
configs=[
triton.Config({"BLOCK_Q": bq, "BLOCK_K": bk})
for bq in [16, 32, 64]
for bk in [32, 64, 128]
],
key=["HK", "HQ"],
cache_results=True,
)
@triton.jit
def _scores_from_logits_kernel(
cu_k,
w_b,
in_m,
in_S, # [B, Hk, ROWS_MAX] f32
LOGITS, # [Nk, Hk, ROWS_MAX] f32, base-2 logits
OUT, # [Nk, Hk] f32
#
QUERY_GROUP_SIZE: tl.constexpr,
STRIDE_M_B,
STRIDE_M_H,
STRIDE_M_R,
STRIDE_S_B,
STRIDE_S_H,
STRIDE_S_R,
STRIDE_LG_NK,
STRIDE_LG_HK,
STRIDE_LG_R,
STRIDE_OUT_NK,
STRIDE_OUT_HK,
BLOCK_Q: tl.constexpr,
BLOCK_K: tl.constexpr,
#
DO_POOL: tl.constexpr, # set True to enable in-place avg pool
KPOOL: tl.constexpr, # kernel size for avg pool (stride=1)
):
b = tl.program_id(0)
hk = tl.program_id(1)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
win = tl.load(w_b + b)
k_eff_end = k_end - win
if (win <= 0) or (k_eff_end <= k_beg):
return
rows_b = win * QUERY_GROUP_SIZE
# === scores over computed region ===
for ks in tl.range(k_beg, k_eff_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_eff_end
scores = tl.zeros([BLOCK_K], dtype=tl.float32)
for row0 in tl.range(0, rows_b, BLOCK_Q):
r_idx = row0 + tl.arange(0, BLOCK_Q)
rmask = r_idx < rows_b
# load m, S for rows
m_ptr = in_m + b * STRIDE_M_B + hk * STRIDE_M_H + row0 * STRIDE_M_R
S_ptr = in_S + b * STRIDE_S_B + hk * STRIDE_S_H + row0 * STRIDE_S_R
m = tl.load(
m_ptr + tl.arange(0, BLOCK_Q) * STRIDE_M_R,
mask=rmask,
other=-float("inf"),
)
S = tl.load(
S_ptr + tl.arange(0, BLOCK_Q) * STRIDE_S_R, mask=rmask, other=0.0
)
valid_row = S > 0
m = tl.where(valid_row, m, 0.0)
S = tl.where(valid_row, S, 1.0)
# load stored logits^T: [BK, BQ]
log_ptrs = (
LOGITS
+ nk[:, None] * STRIDE_LG_NK
+ hk * STRIDE_LG_HK
+ (row0 + tl.arange(0, BLOCK_Q))[None, :] * STRIDE_LG_R
)
s_T = tl.load(
log_ptrs, mask=kmask[:, None] & rmask[None, :], other=-float("inf")
) # [BK, BQ]
# probs^T = exp2(s_T - m) / S, sum over rows
probs_T = tl.math.exp2(s_T - m[None, :]) / S[None, :]
probs_T = tl.where(valid_row[None, :], probs_T, 0.0)
scores += tl.sum(probs_T, 1) # [BK]
if DO_POOL and (KPOOL > 1):
i = tl.arange(0, BLOCK_K)[:, None]
j = tl.arange(0, BLOCK_K)[None, :]
band = (j <= i) & ((i - j) < KPOOL)
band = band & kmask[None, :]
# sum within band
sums = tl.sum(tl.where(band, scores[None, :], 0.0), 1) # [BK]
denom = tl.sum(band, 1).to(tl.float32) # [BK]
denom = tl.where(denom > 0, denom, 1.0)
scores = sums / denom
out_ptrs = OUT + nk * STRIDE_OUT_NK + hk * STRIDE_OUT_HK
tl.store(out_ptrs, scores, mask=kmask)
pad_beg = k_eff_end
pad_end = k_end
if pad_end > pad_beg:
for ks in tl.range(pad_beg, pad_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < pad_end
out_ptrs = OUT + nk * STRIDE_OUT_NK + hk * STRIDE_OUT_HK
tl.store(
out_ptrs, tl.full([BLOCK_K], float("inf"), dtype=tl.float32), mask=kmask
)
@triton_autotune(
configs=[triton.Config({"BLOCK_K": bk}) for bk in [32, 64, 128]],
key=["HK"],
cache_results=True,
)
@triton.jit
def _zscore_per_batch_epilogue(
OUT, # [Nk, Hk], float32
cu_k,
w_b, # [B+1], [B] int32
STRIDE_OUT_NK,
STRIDE_OUT_HK,
HK: tl.constexpr, # Hk
EPS: tl.constexpr, # e.g., 1e-12
BLOCK_K: tl.constexpr, # e.g., 128
):
b = tl.program_id(0)
k_beg = tl.load(cu_k + b)
k_end = tl.load(cu_k + b + 1)
win = tl.load(w_b + b)
k_eff_end = k_end - win
if k_eff_end <= k_beg:
return
sumv = tl.zeros([], dtype=tl.float32)
sumsq = tl.zeros([], dtype=tl.float32)
count = ((k_eff_end - k_beg) * HK).to(tl.float32)
for ks in tl.range(k_beg, k_eff_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_eff_end
for h in tl.range(0, HK):
ptrs = OUT + nk * STRIDE_OUT_NK + h * STRIDE_OUT_HK
vals = tl.load(ptrs, mask=kmask, other=0.0).to(tl.float32)
sumv += tl.sum(vals, 0)
sumsq += tl.sum(vals * vals, 0)
mean = sumv / count
var = tl.maximum(sumsq / count - mean * mean, 0.0)
invstd = 1.0 / tl.sqrt(var + EPS)
for ks in tl.range(k_beg, k_eff_end, BLOCK_K):
nk = ks + tl.arange(0, BLOCK_K)
kmask = nk < k_eff_end
for h in tl.range(0, HK):
ptrs = OUT + nk * STRIDE_OUT_NK + h * STRIDE_OUT_HK
vals = tl.load(ptrs, mask=kmask, other=0.0).to(tl.float32)
vals = (vals - mean) * invstd
tl.store(ptrs, vals, mask=kmask)
def query_aware_key_scores(
q: torch.Tensor, # [N_q, Hq, D]
k: torch.Tensor, # [N_k, Hk, D]
cu_seqlens_q: torch.Tensor, # [B+1], int32
cu_seqlens_k: torch.Tensor, # [B+1], int32
w: torch.Tensor | int, # [B], int32
sm_scale: float = None, # defaults to 1/sqrt(D)
*,
accum_scores: torch.Tensor = None,
accum_blending: float = None,
normalize: bool = False,
) -> Optional[torch.Tensor]:
assert q.stride(-1) == 1 and k.stride(-1) == 1, "last dim must be contiguous"
device = q.device
N_q, Hq, D = q.shape
N_k, Hk, Dk = k.shape
assert (Hq % Hk) == 0, "Hq must be a multiple of Hk"
if sm_scale is None:
sm_scale = 1.0 / math.sqrt(D)
B = cu_seqlens_q.numel() - 1
assert B == cu_seqlens_k.numel() - 1
G = Hq // Hk
if type(w) is int:
max_w = w
w = torch.full((B,), fill_value=w, device=device, dtype=torch.int32)
else:
max_w = int(w.max().item())
assert w.numel() == B
ROWS_MAX = max_w * G
if ROWS_MAX == 0:
return torch.zeros((N_k, Hk), dtype=torch.float32, device=device)
out = torch.empty((N_k, Hk), dtype=torch.float32, device=device)
m_scratch = torch.empty((B, Hk, ROWS_MAX), dtype=torch.float32, device=device)
S_scratch = torch.empty((B, Hk, ROWS_MAX), dtype=torch.float32, device=device)
logits_buf = torch.empty((N_k, Hk, ROWS_MAX), dtype=torch.float32, device=device)
# strides
STRIDE_Q_NQ, STRIDE_Q_HQ, _ = q.stride()
STRIDE_K_NK, STRIDE_K_HK, _ = k.stride()
STRIDE_M_B, STRIDE_M_H, STRIDE_M_R = m_scratch.stride()
STRIDE_S_B, STRIDE_S_H, STRIDE_S_R = S_scratch.stride()
STRIDE_LG_NK, STRIDE_LG_HK, STRIDE_LG_R = logits_buf.stride()
STRIDE_OUT_NK, STRIDE_OUT_HK = out.stride()
def grid(META):
return B, Hk, triton.cdiv(ROWS_MAX, META["BLOCK_Q"])
_lse_and_store_logits_kernel[grid](
q,
k,
cu_seqlens_q,
cu_seqlens_k,
w,
m_scratch,
S_scratch,
logits_buf,
sm_scale,
QUERY_GROUP_SIZE=Hq // Hk,
D=D,
STRIDE_Q_NQ=STRIDE_Q_NQ,
STRIDE_Q_HQ=STRIDE_Q_HQ,
STRIDE_K_NK=STRIDE_K_NK,
STRIDE_K_HK=STRIDE_K_HK,
STRIDE_M_B=STRIDE_M_B,
STRIDE_M_H=STRIDE_M_H,
STRIDE_M_R=STRIDE_M_R,
STRIDE_S_B=STRIDE_S_B,
STRIDE_S_H=STRIDE_S_H,
STRIDE_S_R=STRIDE_S_R,
STRIDE_LG_NK=STRIDE_LG_NK,
STRIDE_LG_HK=STRIDE_LG_HK,
STRIDE_LG_R=STRIDE_LG_R,
ROWS_MAX=ROWS_MAX,
)
_scores_from_logits_kernel[(B, Hk)](
cu_seqlens_k,
w,
m_scratch,
S_scratch,
logits_buf,
out,
QUERY_GROUP_SIZE=Hq // Hk,
STRIDE_M_B=STRIDE_M_B,
STRIDE_M_H=STRIDE_M_H,
STRIDE_M_R=STRIDE_M_R,
STRIDE_S_B=STRIDE_S_B,
STRIDE_S_H=STRIDE_S_H,
STRIDE_S_R=STRIDE_S_R,
STRIDE_LG_NK=STRIDE_LG_NK,
STRIDE_LG_HK=STRIDE_LG_HK,
STRIDE_LG_R=STRIDE_LG_R,
STRIDE_OUT_NK=STRIDE_OUT_NK,
STRIDE_OUT_HK=STRIDE_OUT_HK,
DO_POOL=True,
KPOOL=5,
)
if normalize:
_zscore_per_batch_epilogue[(B,)](
out,
cu_seqlens_k,
w,
STRIDE_OUT_NK,
STRIDE_OUT_HK,
HK=Hk,
EPS=1e-12,
)
if accum_scores is not None:
if accum_blending is not None:
accum_scores.mul_(accum_blending)
accum_scores.add_(out)
return accum_scores
else:
return out
RESERVED_BATCH = 0
# NOTE: Triton `tl.constexpr` is intended for use in kernel signatures/annotations.
# Some Triton builds reject passing `tl.constexpr(...)` objects as constexpr values.
# Keep the runtime value as a plain int and let kernel signatures declare constexpr.
TRITON_RESERVED_BATCH = RESERVED_BATCH
import os
from dataclasses import dataclass
from enum import Enum, auto
from typing import List, Optional
from transformers import AutoConfig
class AttentionBackend(Enum):
FLASH_ATTENTION = auto()
COMPACTOR_TRITON = auto()
@dataclass
class LLMConfig:
"""Configuration for the :class:`LLM` engine.
Parameters
----------
model : str
Hugging Face model identifier (e.g. ``"meta-llama/Meta-Llama-3-8B"``) or
a local model name that can be resolved by
:func:`transformers.AutoConfig.from_pretrained`.
path : str, optional
Local directory containing the model weights. If ``None``, the engine
will attempt to resolve a local snapshot for ``model`` using
:func:`huggingface_hub.snapshot_download`.
max_num_seqs : int, default 256
Upper bound on the number of concurrent batches that the scheduler and
KV-cache manager are allowed to handle. This affects the size of the
page table and some internal buffers.
max_model_len : int, default 40960
Maximum context length (in tokens) that the engine will allocate KV cache
and CUDA graphs for. During initialization this value is clamped to
``hf_config.max_position_embeddings`` for the chosen model.
gpu_memory_utilization : float, default 0.9
Fraction of the total GPU memory that may be used for KV cache and model
activations. Values should be in ``(0, 1]``. If this budget is too small,
the KV-cache manager may raise an error at warmup time due
to insufficient memory.
tensor_parallel_size : int, default 1
Number of tensor-parallel workers to shard the model
across. Must be between 1 and 8, and must evenly divide the model's
number of key/value heads.
enforce_eager : bool, default False
If ``True``, disable CUDA graph capture and always run the model in
eager mode during decoding. This reduces throughput. When ``False``,
the engine will capture and reuse CUDA graphs for supported
batch sizes and sequence lengths.
hf_config : transformers.AutoConfig, optional
Pre-loaded Hugging Face configuration for the model. If ``None``,
it will then be populated automatically based on ``model``.
eos : int, default -1
Primary stop token id (warmup / single-id paths). If ``-1``, the
:class:`LLM` constructor fills this and :attr:`eos_token_ids` from the
tokenizer.
eos_token_ids : list of int, optional
All token ids that terminate generation (e.g. HF tokenizers may expose
``eos_token_id`` as a list for chat models). If ``None``, inferred in
:class:`LLM` from the tokenizer and model type.
kvcache_page_size : int, default 128
Number of tokens stored in a single KV-cache page. Smaller pages improve
allocation flexibility but increase page-table overhead; larger pages
reduce overhead but have coarser granularity.
leverage_sketch_size : int, default 48
Sketch dimension used by the Compactor leverage-score estimator.
attention_backend : AttentionBackend, default AttentionBackend.COMPACTOR_TRITON
Attention implementation to use. ``COMPACTOR_TRITON`` selects the custom
Triton kernels used by Compactor; ``FLASH_ATTENTION`` selects the
FlashAttention3 varlen backend. The COMPACTOR_TRITON tends to be faster
for longer sequence lengths, while FA3 is faster at shorter lengths.
"""
model: str
path: Optional[str] = None
nccl_port: Optional[int] = 1218
max_num_seqs: int = 256
max_model_len: int = 40960
gpu_memory_utilization: float = 0.9
tensor_parallel_size: int = 1
enforce_eager: bool = False
hf_config: AutoConfig | None = None
eos: int = -1
eos_token_ids: Optional[List[int]] = None
kvcache_page_size: int = 128
leverage_sketch_size: int = 48
attention_backend: AttentionBackend = AttentionBackend.COMPACTOR_TRITON
show_progress_bar: bool = True
def __post_init__(self):
if self.path is not None and not os.path.isdir(self.path):
raise NotADirectoryError(f"Engine config dir {self.path} does not exist")
if self.tensor_parallel_size <= 0 or self.tensor_parallel_size > 8:
assert 1 <= self.tensor_parallel_size <= 8
raise ValueError("tensor_parallel_size must be >= 1 and <= 8")
if self.hf_config is None:
self.hf_config = AutoConfig.from_pretrained(self.model)
self.max_model_len = min(
self.max_model_len, self.hf_config.max_position_embeddings
)
from dataclasses import dataclass
@dataclass
class SamplingParams:
temperature: float = 1.0
max_new_tokens: int = 256
def __post_init__(self):
if self.temperature < 0:
raise ValueError("Temperature cannot be negative")
import atexit
import inspect
import logging
from typing import Any, List, Optional, Union
import torch.multiprocessing as mp
from compactor_vllm.compression.compression_config import (
BatchCompressionParams,
SequenceCompressionParams,
)
from compactor_vllm.config.engine_config import LLMConfig
from compactor_vllm.config.sampling_params import SamplingParams
from compactor_vllm.core.model_runner import ModelRunner
from compactor_vllm.models import MODEL_REGISTRY
from compactor_vllm.utils.sequence import Sequence
from transformers import AutoTokenizer
logger = logging.getLogger(__name__)
PromptLike = Union[str, List[int]]
def _infer_stop_token_ids(tokenizer, hf_config) -> list[int]:
"""
Build the set of token ids that should end generation.
Newer HF chat tokenizers often expose ``eos_token_id`` as a *list* of ids.
The engine must not compare generated ids to that list as a single ``int``;
see :attr:`LLMConfig.eos_token_ids` and decode-time ``torch.isin``.
Qwen chat uses ``</think>`` (im_end) as the assistant turn boundary; include it
when present in ``additional_special_tokens`` / ``added_tokens_encoder``. We
avoid loose substring matches like ``\"end\"`` that can tag unrelated tokens.
"""
raw = tokenizer.eos_token_id
ids: list[int] = []
if isinstance(raw, (list, tuple)):
ids.extend(int(x) for x in raw)
elif raw is not None:
ids.append(int(raw))
unk_id = getattr(tokenizer, "unk_token_id", None)
def _maybe_add_tid(tid: int) -> None:
if not isinstance(tid, int) or tid < 0:
return
if unk_id is not None and tid == unk_id:
return
if tid not in ids:
ids.append(tid)
model_type = getattr(hf_config, "model_type", None)
if model_type in ("qwen2", "qwen3", "qwen2_moe", "qwen3_moe"):
enc = getattr(tokenizer, "added_tokens_encoder", None)
if isinstance(enc, dict):
for key, tid in enc.items():
if isinstance(key, str) and "im_end" in key:
_maybe_add_tid(int(tid))
for extra in getattr(tokenizer, "additional_special_tokens", []) or []:
if not isinstance(extra, str) or "im_end" not in extra:
continue
try:
tid = tokenizer.convert_tokens_to_ids(extra)
except (TypeError, ValueError, KeyError):
continue
_maybe_add_tid(tid)
if not ids:
raise ValueError(
"Could not infer stop token ids from the tokenizer; set "
"LLMConfig(eos_token_ids=[...]) explicitly."
)
return ids
def _merge_apply_chat_template_kwargs(
tokenizer,
user_kwargs: Optional[dict[str, Any]],
) -> dict[str, Any]:
"""
Merge user kwargs with defaults for HF chat templates that support them.
Qwen3 (and similar) instruct models expect `add_generation_prompt=True` so
the first generated token continues the assistant turn; without it, output
can repeat punctuation / template fragments. `enable_thinking=False` avoids
the Qwen3 reasoning channel when the tokenizer supports it.
"""
out = dict(user_kwargs or {})
try:
sig = inspect.signature(tokenizer.apply_chat_template)
except (TypeError, ValueError):
return out
if "add_generation_prompt" in sig.parameters and "add_generation_prompt" not in out:
out["add_generation_prompt"] = True
if "enable_thinking" in sig.parameters and "enable_thinking" not in out:
out["enable_thinking"] = False
return out
def _runner_entry(config: LLMConfig, rank: int, evt):
runner = None
try:
runner = ModelRunner(config, rank, evt)
runner.loop()
except Exception as e:
logging.exception(f"Rank {rank}: {repr(e)}")
finally:
if runner is not None:
runner.exit()
class LLMEngine:
"""High-level engine coordinating model runners and scheduling"""
def __init__(self, config: LLMConfig):
self.config = config
if self.config.hf_config.model_type not in MODEL_REGISTRY:
raise ValueError(f"Unknown model {self.config.model}")
if config.path is None:
from huggingface_hub import snapshot_download
self.config.path = snapshot_download(
repo_id=config.model, local_files_only=True
)
logger.info(f"Using {self.config.model} snapshot @ {self.config.path}")
self.tokenizer = AutoTokenizer.from_pretrained(self.config.model, use_fast=True)
if self.config.eos_token_ids is None:
if self.config.eos != -1:
self.config.eos_token_ids = [int(self.config.eos)]
else:
self.config.eos_token_ids = _infer_stop_token_ids(
self.tokenizer, self.config.hf_config
)
else:
self.config.eos_token_ids = [int(x) for x in self.config.eos_token_ids]
self.config.eos_token_ids = sorted(set(self.config.eos_token_ids))
if self.config.eos == -1:
self.config.eos = int(self.config.eos_token_ids[0])
else:
self.config.eos = int(self.config.eos)
if self.config.eos not in self.config.eos_token_ids:
self.config.eos_token_ids = sorted(
self.config.eos_token_ids + [self.config.eos]
)
self.ps = []
world_size = int(self.config.tensor_parallel_size)
self.events = []
if world_size > 1:
ctx = mp.get_context("spawn")
for r in range(1, world_size):
event = ctx.Event()
p = ctx.Process(
target=_runner_entry,
args=(self.config, r, event),
daemon=True,
)
p.start()
self.ps.append(p)
self.events.append(event)
self.master_model_runner = ModelRunner(
self.config, rank=0, peer_events=self.events
)
atexit.register(self.exit)
def exit(self):
if getattr(self, "_exited", False):
return
self._exited = True
runner = getattr(self, "master_model_runner", None)
if runner is not None:
try:
runner.exit()
except Exception:
logger.exception("Failed to exit master ModelRunner cleanly")
for p in self.ps:
if p.is_alive():
p.terminate()
p.join(timeout=1.0)
if hasattr(self, "events"):
self.events.clear()
def tokenize_prompt(self, prompt: PromptLike, **tokenizer_kwargs) -> List[int]:
"""
Turn a raw prompt into token IDs.
"""
if isinstance(prompt, str):
return self.tokenizer(prompt, **tokenizer_kwargs)["input_ids"]
else:
return list(prompt)
def detokenize_prompt(
self, sequences: List[Sequence], **detokenizer_kwargs
) -> List[str]:
"""
Turn completed Sequences into strings.
"""
defaults: dict[str, Any] = {"skip_special_tokens": True}
merged = {**defaults, **detokenizer_kwargs}
return self.tokenizer.batch_decode(
[s.completion_token_ids for s in sequences], **merged
)
def _build_sequences(
self,
prompts: List[PromptLike] | PromptLike,
sampling_params: SamplingParams | List[SamplingParams],
per_sequence_compression_params: Optional[
SequenceCompressionParams | List[SequenceCompressionParams]
] = None,
tokenizer_kwargs: Optional[dict[str, Any]] = None,
) -> List[Sequence]:
"""
Build Sequence objects from prompts, sampling params, and optional
per-sequence compression parameters.
"""
tokenizer_kwargs = {} if tokenizer_kwargs is None else tokenizer_kwargs
if not isinstance(prompts, list):
prompts = [prompts]
if isinstance(sampling_params, SamplingParams):
sampling_params_list: List[SamplingParams] = [sampling_params] * len(
prompts
)
else:
sampling_params_list = sampling_params
assert len(sampling_params_list) == len(prompts), (
"sampling_params list must match prompts length"
)
if per_sequence_compression_params is None:
compression_params_list: List[SequenceCompressionParams] = [
SequenceCompressionParams(1.0) for _ in prompts
]
elif isinstance(per_sequence_compression_params, SequenceCompressionParams):
compression_params_list = [per_sequence_compression_params] * len(prompts)
else:
# list-like
assert len(per_sequence_compression_params) == len(prompts), (
"per_sequence_compression_params list must match prompts length"
)
compression_params_list = list(per_sequence_compression_params)
seqs: List[Sequence] = []
for prompt, sparams, cparams in zip(
prompts, sampling_params_list, compression_params_list
):
token_ids = self.tokenize_prompt(prompt, **tokenizer_kwargs)
if cparams.protected_first_tokens + cparams.protected_last_tokens >= len(token_ids):
cparams.compression_ratio = 1.0
seqs.append(
Sequence(
prompt_token_ids=token_ids,
sampling_params=sparams,
compression_params=cparams,
)
)
return seqs
def generate(
self,
prompts: List[PromptLike] | PromptLike,
sampling_params: SamplingParams | List[SamplingParams],
batch_compression_params: BatchCompressionParams,
*,
per_sequence_compression_params: Union[
List[SequenceCompressionParams], SequenceCompressionParams
] = None,
tokenizer_kwargs: Optional[dict[str, Any]] = None,
detokenizer_kwargs: Optional[dict[str, Any]] = None,
return_sequences: bool = False,
) -> List[str] | tuple[List[str], List[Sequence]]:
"""
Accept prompts and return completed Sequences.
Args:
:param prompts:
Single prompt or list of prompts, each either a raw text prompt,
or pre-tokenized input IDs.
:param sampling_params:
A single SamplingParams for all prompts in this batch or a list of
SamplingParams with the same length as ``prompts``.
:param batch_compression_params:
Compression settings for this batch.
:param per_sequence_compression_params:
Per-sequence compression parameters, including the compression
ratio to be applied and the size of the protected regions of the
sequence (how many start tokens and end tokens to keep uncompressed).
If a SequenceCompressionParams instance, the same params will be
applied to all sequences in this batch; if a list is provided,
each SequenceCompressionParams will be attached to the corresponding
prompt in the batch.
:param tokenizer_kwargs:
Extra kwargs forwarded to ``tokenizer(...)`` when tokenizing
string prompts.
:param detokenizer_kwargs:
Passed through to `tokenizer.batch_decode`.
:param return_sequences:
Whether to return sequence objects or not
Returns:
:return List[Sequence]:
One Sequence per input prompt, with `completion_token_ids`
filled in after generation.
"""
tokenizer_kwargs = {} if tokenizer_kwargs is None else tokenizer_kwargs
detokenizer_kwargs = {} if detokenizer_kwargs is None else detokenizer_kwargs
seqs = self._build_sequences(
prompts,
sampling_params=sampling_params,
per_sequence_compression_params=per_sequence_compression_params,
tokenizer_kwargs=tokenizer_kwargs,
)
self.master_model_runner.generate(seqs, batch_compression_params)
output_strings = self.detokenize_prompt(seqs, **detokenizer_kwargs)
if return_sequences:
return output_strings, seqs
return output_strings
def generate_chat(
self,
messages_batch: List[List[dict]],
sampling_params: SamplingParams | List[SamplingParams],
batch_compression_params: BatchCompressionParams,
per_sequence_compression_params: Union[
SequenceCompressionParams, List[SequenceCompressionParams]
],
*,
tokenizer_kwargs: Optional[dict[str, Any]] = None,
detokenizer_kwargs: Optional[dict[str, Any]] = None,
return_sequences: bool = False,
) -> List[str] | tuple[List[str], List[Sequence]]:
"""
Convenience API for chat-style prompts using HF `apply_chat_template`.
Args:
:param messages_batch:
List of conversations, where each conversation is a list of
message dicts like:
{"role": "system" | "user" | "assistant", "content": str}
:param sampling_params:
A single SamplingParams for all prompts in this batch or a list of
SamplingParams with the same length as ``prompts``.
:param batch_compression_params:
Batch Level compression settings. Can set compression_method.
:param per_sequence_compression_params:
Per-sequence compression parameters, including the compression
ratio to be applied and the size of the protected regions of the
sequence (how many start tokens and end tokens to keep uncompressed).
If a SequenceCompressionParams instance, the same params will be
applied to all sequences in this batch; if a list is provided,
each SequenceCompressionParams will be attached to the corresponding
conversation in the batch.
:param tokenizer_kwargs:
Passed through to `tokenizer.apply_chat_template`.
:param detokenizer_kwargs:
Passed through to `tokenizer.batch_decode`.
:param return_sequences:
Whether to return sequence objects or not
Returns:
:return List[str] or tuple[List[str], List[Sequence]]:
One string per conversation.
"""
prompts_token_ids: List[List[int]] = []
tokenizer_kwargs = _merge_apply_chat_template_kwargs(
self.tokenizer, tokenizer_kwargs
)
detokenizer_kwargs = {} if detokenizer_kwargs is None else detokenizer_kwargs
for messages in messages_batch:
input_ids = self.tokenizer.apply_chat_template(
messages,
tokenize=True,
**tokenizer_kwargs,
)
if hasattr(input_ids, "tolist"):
input_ids = input_ids.tolist()
prompts_token_ids.append(input_ids)
return self.generate(
prompts_token_ids,
sampling_params=sampling_params,
batch_compression_params=batch_compression_params,
per_sequence_compression_params=per_sequence_compression_params,
tokenizer_kwargs=tokenizer_kwargs,
detokenizer_kwargs=detokenizer_kwargs,
return_sequences=return_sequences,
)
def generate_from_sequences(
self,
seqs: List[Sequence],
batch_compression_params: BatchCompressionParams,
) -> List[Sequence]:
"""
Args:
:param seqs:
List of Sequence instances
:param batch_compression_params:
Compression settings.
Returns:
:return List[Sequence]:
Same list, mutated in-place with completions.
"""
self.master_model_runner.generate(seqs, batch_compression_params)
return seqs
import logging
from typing import Iterable, List, Optional
import torch
import torch.distributed as dist
from compactor_vllm.config.engine_config import LLMConfig
from compactor_vllm.kv_cache.page_table import KVAllocationStatus, PagedKVCache
from torch import nn
logger = logging.getLogger(__name__)
class KVCacheManager:
def __init__(self, rank: int, config: LLMConfig):
super().__init__()
hf_config = config.hf_config
self.rank = rank
self.gpu_frac = config.gpu_memory_utilization
self.page_size = config.kvcache_page_size
self.world_size = config.tensor_parallel_size
self.max_num_batches = config.max_num_seqs
self.max_model_len = config.max_model_len
self.num_layers = hf_config.num_hidden_layers
self.model_dtype = hf_config.torch_dtype
self.head_dim = getattr(hf_config, "head_dim", None)
self.max_pages_per_batch = (
self.max_model_len + self.page_size - 1
) // self.page_size
self.num_kv_heads = hf_config.num_key_value_heads // dist.get_world_size()
assert hf_config.num_key_value_heads % dist.get_world_size() == 0, (
"world size needs to divide num_kv_heads"
)
self.num_pages = None
self.paged_cache: Optional[PagedKVCache] = None
self.max_batched_tokens = None
self.seq_id_to_batch = {}
def allocate_sequences(
self, seq_ids: List[int], max_positions: List[int]
) -> (bool, Optional[torch.Tensor]):
batch_mapping = []
for seq_id, len_to_alloc in zip(seq_ids, max_positions):
if seq_id not in self.seq_id_to_batch:
batch_id = self.paged_cache.new_batch()
if batch_id is None:
logger.warning("Failed to allocate batch!")
return False, None
self.seq_id_to_batch[seq_id] = int(batch_id)
batch_mapping.append(self.seq_id_to_batch[seq_id])
if (
alloc_status := self.paged_cache.reserve_tokens(
self.seq_id_to_batch[seq_id], len_to_alloc
)
) != KVAllocationStatus.SUCCESS:
logger.warning(f"Failed to allocate pages ({alloc_status})!")
return False, None
batch_mapping = torch.as_tensor(batch_mapping, dtype=torch.int32, device="cuda")
return True, batch_mapping
def free_sequences(self, seq_ids: Iterable[int]):
for seq_id in seq_ids:
global_batch_id = self.seq_id_to_batch.pop(seq_id, None)
self.paged_cache.free_batch(global_batch_id)
def init_cache(self, model: nn.Module):
self.num_pages = self.get_num_pages(self.gpu_frac, self.max_pages_per_batch)
self.paged_cache = PagedKVCache(
num_layers=self.num_layers,
H_kv=self.num_kv_heads,
head_dim=self.head_dim,
page_size=self.page_size,
num_pages=int(self.num_pages),
max_num_batches=self.max_num_batches,
device=f"cuda:{self.rank}",
dtype=self.model_dtype,
max_logical_pages_per_head=int(self.max_pages_per_batch),
)
self._assign_cache_to_layers(model)
def _assign_cache_to_layers(self, model) -> None:
for layer_index, layer in enumerate(model.model.layers):
attn = layer.self_attn.attn
k, v, pt, bh = self.paged_cache.layer_slices(layer_index)
attn.k_cache = k
attn.v_cache = v
attn.page_table = pt
attn.bh_seq_lens = bh
attn.page_size = self.page_size
def get_num_pages(self, frac: float, n_logical_pages_max: int):
free, total = torch.cuda.mem_get_info()
used = total - free
stats = torch.cuda.memory_stats()
peak = int(stats["allocated_bytes.all.peak"])
current = int(stats["allocated_bytes.all.current"])
bytes_for_kv_budget = int(total * frac * 0.9) - used - peak + current
if bytes_for_kv_budget <= 0:
raise RuntimeError(
f"Insufficient memory for KV cache."
f"Try increasing gpu_memory_utilization (currently {frac:.2f})."
)
# page_table[L, B, H_kv, N_LOGICAL_PAGES_MAX] + bh_seq_lens[L, B, H_kv]
int32_sz = torch.empty((), dtype=torch.int32).element_size() # 4
page_table_bytes_per_layer = (
self.max_num_batches
* self.num_kv_heads
* n_logical_pages_max
* int32_sz # page_table
+ self.max_num_batches * self.num_kv_heads * int32_sz
)
total_page_table_bytes = self.num_layers * page_table_bytes_per_layer
kv_bytes_net = bytes_for_kv_budget - total_page_table_bytes
if kv_bytes_net <= 0:
raise RuntimeError(
"page-table footprint exceeds KV cache budget. "
f"reduce max_num_seqs ({self.max_num_batches}) "
f"or increase kv_cache_mem_fraction (currently {frac:.2f})."
)
dtype_sz = torch.empty((), dtype=self.model_dtype).element_size()
bytes_per_page_across_layers = self.num_layers * (
2 * self.page_size * self.head_dim * dtype_sz
)
return max(1, kv_bytes_net // bytes_per_page_across_layers)
def estimate_max_batched_tokens(
self,
warmup_tokens: int,
bytes_used_before_warmup: int,
bytes_peak_after_warmup: int,
) -> int:
"""
Estimate the max total number of tokens that can be processed concurrently
without OOM.
"""
assert warmup_tokens > 0, "warmup_tokens must be > 0"
# activation bytes per token
warmup_delta = max(
0, int(bytes_peak_after_warmup) - int(bytes_used_before_warmup)
)
bytes_per_token = max(1, (warmup_delta + warmup_tokens - 1) // warmup_tokens)
free, total = torch.cuda.mem_get_info()
target = int(total * self.gpu_frac)
used_now = int(total - free)
# reserve headroom equal to the gap between peak and current allocations seen so far
stats = torch.cuda.memory_stats()
peak_cur = int(stats.get("allocated_bytes.all.peak", 0))
cur_now = int(stats.get("allocated_bytes.all.current", 0))
cushion = max(0, peak_cur - cur_now)
activation_budget = int(max(0, target - used_now - cushion) * 0.95)
max_tokens_per_batch = activation_budget // bytes_per_token
max_tokens_in_cache = (self.num_pages * self.page_size) // self.num_kv_heads
# round to lower multiple of page size
max_tokens_per_batch = (max_tokens_per_batch // self.page_size) * self.page_size
max_tokens_in_cache = (max_tokens_in_cache // self.page_size) * self.page_size
self.max_batched_tokens = min(max_tokens_in_cache, max_tokens_per_batch)
return self.max_batched_tokens
@property
def num_free_batches(self) -> int:
return len(self.paged_cache.free_batches)
@property
def num_free_pages(self) -> int:
return min(len(fp) for fp in self.paged_cache.free_pages)
def reclaim_pages(
self,
seq_ids_to_reclaim: Iterable[int],
future_reserved_buffer: List[int] | torch.Tensor,
) -> int:
approximate_bytes_freed = 0
for i, seq_id in enumerate(seq_ids_to_reclaim):
batch_idx = self.seq_id_to_batch[seq_id]
approximate_bytes_freed += self.paged_cache.reclaim_pages(
batch_idx, future_reserved_buffer[i]
)
return approximate_bytes_freed
import atexit
import logging
import inspect
from typing import List, Optional
import torch
import torch.distributed as dist
from compactor_vllm.attention.sparse_decode_kernel import num_splits_heuristic
from compactor_vllm.compression.compression_config import BatchCompressionParams
from compactor_vllm.config.constants import RESERVED_BATCH
from compactor_vllm.config.engine_config import AttentionBackend, LLMConfig
from compactor_vllm.core.memory_manager import KVCacheManager
from compactor_vllm.core.scheduler import Scheduler
from compactor_vllm.layers.sampler import Sampler
from compactor_vllm.models import MODEL_REGISTRY
from compactor_vllm.utils.arguments import (
DecodeBatchArguments,
DecodeBatchOutput,
PackedTensorArguments,
PrefillBatchArguments,
)
from compactor_vllm.utils.context import CompressionContext, reset_context, set_context
from compactor_vllm.utils.sequence import Sequence
from torch.multiprocessing import Event
from tqdm import tqdm
logger = logging.getLogger(__name__)
class ModelRunner:
"""Per-rank execution loop. Manages model, sampler, KV cache, and warmup"""
def __init__(
self,
config: LLMConfig,
rank: int,
batch_ready: Optional[Event] = None,
peer_events: List[Event] = None,
):
self.rank = rank
self.config = config
_dev = torch.device(f"cuda:{rank}")
assert config.eos_token_ids is not None and len(config.eos_token_ids) > 0, (
"LLMConfig.eos_token_ids must be set (filled in LLMEngine from tokenizer)."
)
self._stop_token_ids = torch.tensor(
config.eos_token_ids, dtype=torch.int64, device=_dev
)
hf_config = config.hf_config
self.enforce_eager = config.enforce_eager
self.world_size = config.tensor_parallel_size
self.leverage_sketch_size = config.leverage_sketch_size
self.show_progress_bar = config.show_progress_bar
self.max_num_batches = config.max_num_seqs
self.max_model_len = config.max_model_len
self.num_layers = hf_config.num_hidden_layers
self.model_dtype = hf_config.torch_dtype
self.head_dim = getattr(hf_config, "head_dim", None)
init_kwargs = {}
if "device_id" in inspect.signature(dist.init_process_group).parameters:
init_kwargs["device_id"] = torch.device(f"cuda:{rank}")
dist.init_process_group(
"nccl",
f"tcp://localhost:{config.nccl_port}",
world_size=self.world_size,
rank=rank,
**init_kwargs,
)
torch.cuda.set_device(rank)
default_dtype = torch.get_default_dtype()
torch.set_default_dtype(hf_config.torch_dtype)
torch.set_default_device("cuda")
model_type = hf_config.model_type
self.model = MODEL_REGISTRY[model_type](hf_config)
self.model.load_model(
config.path, use_tqdm=self.is_master and self.show_progress_bar
)
self.sampler = Sampler()
pre_warmup_mem = torch.cuda.memory_stats().get("allocated_bytes.all.current", 0)
self.warmup(
num_warmup_tokens=self.max_model_len,
attention_backend=AttentionBackend.FLASH_ATTENTION,
)
post_warmup_peak = torch.cuda.memory_stats().get("allocated_bytes.all.peak", 0)
self.kv_manager = KVCacheManager(rank, config)
self.kv_manager.init_cache(self.model)
self.store_stream: Optional[torch.cuda.Stream] = torch.cuda.Stream()
torch.set_default_device("cpu")
torch.set_default_dtype(default_dtype)
self.batch_ready = batch_ready
self.peer_events = peer_events if peer_events is not None else []
self.captured_graphs = {}
self.min_captured_len = {}
self.max_batched_tokens = self.kv_manager.estimate_max_batched_tokens(
self.max_model_len, pre_warmup_mem, post_warmup_peak
)
if self.is_master:
logger.info(f"Estimated max batched tokens of {self.max_batched_tokens}")
if self.config.attention_backend == AttentionBackend.COMPACTOR_TRITON:
self.warmup(
num_warmup_tokens=self.max_model_len,
attention_backend=AttentionBackend.COMPACTOR_TRITON,
)
if not self.enforce_eager:
bs = [1 << i for i in range(self.max_num_batches.bit_length())]
for bs in (
tqdm(bs, desc="Capturing CUDA Graphs")
if self.is_master and self.show_progress_bar
else bs
):
for seq_len in [1024, 4096, 8192, 16384]:
self.capture_cudagraph(bs, seq_len)
self.packed_args = PackedTensorArguments(
rank=self.rank,
max_batched_tokens=self.max_batched_tokens,
config=self.config,
)
atexit.register(self.exit)
@torch.inference_mode()
def warmup(self, num_warmup_tokens: int, attention_backend: AttentionBackend):
if self.rank == 0:
if attention_backend == AttentionBackend.COMPACTOR_TRITON:
backend_name = "Compactor Triton"
else:
backend_name = "Flash"
logger.info(f"Warming up with {backend_name} Attention Backend")
device = torch.device(f"cuda:{self.rank}")
input_ids = torch.tensor(
[self.config.eos] * num_warmup_tokens, device=device, dtype=torch.int64
)
positions = torch.arange(num_warmup_tokens, device=device, dtype=torch.int64)
cu_seqlens_q = torch.tensor(
[0, num_warmup_tokens], device=device, dtype=torch.int32
)
cu_seqlens_k = torch.tensor(
[0, num_warmup_tokens], device=device, dtype=torch.int32
)
if attention_backend == AttentionBackend.COMPACTOR_TRITON:
success, batch_mapping = self.kv_manager.allocate_sequences(
[-1], [num_warmup_tokens]
)
assert success
else:
batch_mapping = None
set_context(
is_prefill=True,
do_compression=False,
cu_seqlens_q=cu_seqlens_q,
cu_seqlens_k=cu_seqlens_k,
max_seqlen_q=num_warmup_tokens,
max_seqlen_k=num_warmup_tokens,
batch_mapping=batch_mapping,
attention_backend=attention_backend,
)
for _ in range(2):
torch.cuda.reset_peak_memory_stats()
self.model.compute_logits(self.model(input_ids, positions))
dist.barrier()
if attention_backend == AttentionBackend.COMPACTOR_TRITON:
self.kv_manager.paged_cache.bh_seq_lens.index_fill_(
1, batch_mapping.to(torch.long), 0
)
reset_context()
if attention_backend == AttentionBackend.COMPACTOR_TRITON:
self.kv_manager.free_sequences([-1])
def exit(self):
if getattr(self, "_exited", False):
return
self._exited = True
try:
if hasattr(self, "captured_graphs"):
self.captured_graphs.clear()
finally:
if dist.is_initialized():
dist.destroy_process_group()
def loop(self):
while True:
if self.batch_ready.wait(1.0):
self._process_batches_peer()
@torch.inference_mode()
def run_prefill(
self, prefill_args: PrefillBatchArguments, batch_mapping: torch.Tensor
):
assert prefill_args.B > 0 and prefill_args.N > 0
max_bh_len = (
self.kv_manager.paged_cache.bh_seq_lens.index_select(1, index=batch_mapping)
.max()
.item()
)
compression_context = CompressionContext(
compression_method=prefill_args.compression_method,
compression_chunk_size=prefill_args.compression_chunk_size,
batch_tokens_to_retain=prefill_args.batch_tokens_to_retain,
max_tokens_to_retain=prefill_args.max_tokens_to_retain,
context_lens=prefill_args.context_lens.tolist(),
PHI=prefill_args.PHI,
sketch_dimension=self.leverage_sketch_size,
protected_first_tokens=prefill_args.protected_first,
protected_last_tokens=prefill_args.protected_last,
compression_ratio=prefill_args.compression_ratio,
)
set_context(
is_prefill=True,
do_compression=prefill_args.do_compression,
cu_seqlens_q=prefill_args.cu_seqlens_q,
cu_seqlens_k=prefill_args.cu_seqlens_k,
max_seqlen_q=prefill_args.max_seqlen_q,
max_seqlen_k=prefill_args.max_seqlen_k,
batch_mapping=batch_mapping,
max_bh_len=max_bh_len,
compression_context=compression_context,
STORE_STREAM=self.store_stream,
attention_backend=self.config.attention_backend,
)
logits = self.model.compute_logits(
self.model(prefill_args.input_ids, prefill_args.positions)
)
reset_context()
return logits
def maybe_broadcast(self, tensor: torch.Tensor):
if self.world_size > 1:
return dist.broadcast(tensor, src=0)
return None
def maybe_release_peers(self, do_release=False):
if self.world_size > 1:
if self.is_master:
if do_release:
for event in self.peer_events:
event.clear()
dist.barrier()
else:
dist.barrier()
@torch.inference_mode()
def generate(
self,
all_sequences: List[Sequence],
batch_compression_params: Optional[BatchCompressionParams] = None,
):
assert self.is_master, "generate can only be called on the master process"
for begin_execution_event in self.peer_events:
begin_execution_event.set()
if batch_compression_params is None:
batch_compression_params = BatchCompressionParams()
self._process_batches_master(all_sequences, batch_compression_params)
@property
def is_master(self):
return self.rank == 0
@torch.inference_mode()
def _process_batches_master(
self,
all_sequences: List[Sequence],
batch_compression_params: BatchCompressionParams,
):
assert self.is_master
compression_details = f"Applying Compression Method: {batch_compression_params.compression_method}"
if any(seq.compression_params.compression_ratio < 1.0 for seq in all_sequences):
logger.info(compression_details)
scheduler = Scheduler(
all_sequences=all_sequences,
kv_manager=self.kv_manager,
use_tqdm=self.show_progress_bar,
)
decode_batch = DecodeBatchArguments()
decode_flags = torch.empty(2, dtype=torch.int32, device="cuda")
while not scheduler.is_finished():
sequences = scheduler.get_prefill_batch()
seq_ids_cpu = [seq.seq_id for seq in sequences]
scheduler.add_running_sequence_ids(seq_ids_cpu, update_status=True)
temps = torch.tensor(
[s.sampling_params.temperature for s in sequences],
dtype=torch.float32,
pin_memory=True,
).cuda(non_blocking=True)
prefill_arguments = self.packed_args.build_prefill_args(
sequences, batch_compression_params=batch_compression_params
)
max_ctx_lens = (
prefill_arguments.max_new_tokens + prefill_arguments.context_lens
)
success, batch_mapping = self.kv_manager.allocate_sequences(
seq_ids_cpu, max_ctx_lens.tolist()
)
assert success, "failed to allocate pages for sequences"
logits = self.run_prefill(prefill_arguments, batch_mapping)
# Must match prefill `positions` dtype (int64). `context_lens` is int32
# from the packed buffer; using int32 here breaks RoPE indexing
# (`cos_sin_cache[positions]`) on CUDA for decode vs prefill.
positions = prefill_arguments.context_lens.to(dtype=torch.int64)
token_ids = self.sampler(logits, temps)
# Prefill KV writes + bh_seq_lens updates run on STORE_STREAM; reclaim
# reads bh_seq_lens on the default stream and must not race.
if self.store_stream is not None:
torch.cuda.default_stream().wait_stream(self.store_stream)
# TODO: synchronize page counts accross dist
if self.world_size == 1:
self.kv_manager.reclaim_pages(
seq_ids_cpu, prefill_arguments.max_new_tokens
)
# with logging_redirect_tqdm():
# logger.info(
# f"Reclaimed {reclaimed_bytes / 1e6:.2f} MB from the KV cache"
# )
if scheduler.any_pending_sequences():
num_pending_batches = (
0
if decode_batch.token_ids is None
else decode_batch.token_ids.shape[0]
)
occupancy = int((num_pending_batches + len(seq_ids_cpu)) * 0.66)
else:
occupancy = -1
run_decode = not scheduler.can_prefill_another_batch()
decode_batch = decode_batch.update(
batch_mapping,
token_ids,
positions,
max_ctx_lens,
prefill_arguments.seq_ids,
temps,
occupancy,
)
if self.world_size > 1:
decode_flags[0] = int(run_decode)
decode_flags[1] = occupancy
self.maybe_broadcast(decode_flags)
if not run_decode:
continue
if self.store_stream is not None:
torch.cuda.default_stream().wait_stream(self.store_stream)
decode_output, decode_batch = self.run_decode_loop(decode_batch)
finished_sequence_ids = scheduler.get_finished_sequence_ids_from_unfinished(
decode_batch.seq_ids.tolist()
)
scheduler.record_finished_sequence_ids(
finished_sequence_ids, update_status=True
)
self.kv_manager.free_sequences(finished_sequence_ids)
self.maybe_release_peers(scheduler.is_finished())
scheduler.update_sequences(
decode_output.output_tokens.tolist(),
decode_output.output_seq_ids.tolist(),
)
scheduler.close()
@torch.inference_mode()
def _process_batches_peer(self):
assert not self.is_master
scheduler = Scheduler([], kv_manager=self.kv_manager)
decode_batch = DecodeBatchArguments()
decode_flags = torch.empty(2, dtype=torch.int32, device="cuda")
while self.batch_ready.is_set():
prefill_arguments = self.packed_args.build_prefill_args()
B = prefill_arguments.B
max_ctx_lens = (
prefill_arguments.max_new_tokens + prefill_arguments.context_lens
)
seq_ids_cpu = prefill_arguments.seq_ids.tolist()
scheduler.add_running_sequence_ids(seq_ids_cpu)
success, batch_mapping = self.kv_manager.allocate_sequences(
seq_ids_cpu, max_ctx_lens.tolist()
)
assert success, "failed to allocate pages for sequences"
self.run_prefill(prefill_arguments, batch_mapping)
positions = prefill_arguments.context_lens.to(dtype=torch.int64)
self.maybe_broadcast(decode_flags)
run_decode = bool(decode_flags[0].item())
occupancy = int(decode_flags[1].item())
token_ids = torch.empty(B, dtype=torch.int64, device="cuda")
decode_batch = decode_batch.update(
batch_mapping,
token_ids,
positions,
max_ctx_lens,
prefill_arguments.seq_ids,
None, # temps not used in peer process
occupancy,
)
if not run_decode:
continue
if self.store_stream is not None:
torch.cuda.default_stream().wait_stream(self.store_stream)
_, decode_batch = self.run_decode_loop(decode_batch)
finished_sequence_ids = scheduler.get_finished_sequence_ids_from_unfinished(
decode_batch.seq_ids.tolist()
)
scheduler.record_finished_sequence_ids(finished_sequence_ids)
self.kv_manager.free_sequences(finished_sequence_ids)
self.maybe_release_peers()
scheduler.close()
@torch.inference_mode()
def run_decode_loop(
self,
decode_batch: DecodeBatchArguments,
) -> tuple[DecodeBatchOutput, DecodeBatchArguments]:
if self.is_master:
num_stashed_batches = decode_batch.num_stashed_batches
tok_buffer = [
decode_batch.token_ids[num_stashed_batches:].to(
"cpu", non_blocking=True
)
]
seq_buffer = [
decode_batch.seq_ids[num_stashed_batches:].to("cpu", non_blocking=True)
]
while True:
self.maybe_broadcast(decode_batch.token_ids)
not_stopped = ~torch.isin(decode_batch.token_ids, self._stop_token_ids)
running_batches = (decode_batch.positions < decode_batch.max_ctx_lens) & (
not_stopped
)
decode_batch.token_ids = torch.masked_select(
decode_batch.token_ids, running_batches
)
decode_batch.positions = torch.masked_select(
decode_batch.positions, running_batches
)
decode_batch.batch_mapping = torch.masked_select(
decode_batch.batch_mapping, running_batches
)
decode_batch.max_ctx_lens = torch.masked_select(
decode_batch.max_ctx_lens, running_batches
)
decode_batch.seq_ids = torch.masked_select(
decode_batch.seq_ids, running_batches
)
if self.is_master:
decode_batch.temps = torch.masked_select(
decode_batch.temps, running_batches
)
num_remaining = decode_batch.token_ids.numel()
if (
num_remaining == 0
or num_remaining <= decode_batch.desired_batch_occupancy
):
decode_batch.num_stashed_batches = num_remaining
break
if self.enforce_eager:
set_context(
is_prefill=False,
do_compression=False,
batch_mapping=decode_batch.batch_mapping,
)
logits = self.model.compute_logits(
self.model(decode_batch.token_ids, decode_batch.positions)
)
else:
logits = self.run_graph_decode(
decode_batch.token_ids,
decode_batch.positions,
decode_batch.batch_mapping,
)
if self.is_master:
decode_batch.token_ids = self.sampler(logits, decode_batch.temps)
tok_buffer.append(decode_batch.token_ids.to("cpu", non_blocking=True))
seq_buffer.append(decode_batch.seq_ids.to("cpu", non_blocking=True))
decode_batch.positions += 1
if self.is_master:
# non_blocking D2H copies must finish before cat/tolist read CPU data.
torch.cuda.synchronize()
output = DecodeBatchOutput(
output_tokens=torch.cat(tok_buffer),
output_seq_ids=torch.cat(seq_buffer),
)
else:
output = DecodeBatchOutput(None, None)
return output, decode_batch
@torch.inference_mode()
def run_graph_decode(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
batch_mapping: torch.Tensor,
):
set_context(
is_prefill=False,
do_compression=False,
batch_mapping=batch_mapping,
)
bs = input_ids.shape[0]
graph_dict = self.get_cuda_graph(bs, int(positions.max()))
graph_dict["input_ids"][:bs] = input_ids
graph_dict["positions"][:bs] = positions
graph_dict["batch_mapping"].fill_(RESERVED_BATCH)
graph_dict["batch_mapping"][:bs] = batch_mapping
graph_dict["graph"].replay()
return (
graph_dict["logits"][:bs]
if graph_dict["logits"] is not None
else graph_dict["logits"]
)
@torch.inference_mode()
def capture_cudagraph(self, batch_size: int, max_seqlen_k: int):
dist.barrier()
device = torch.device("cuda")
logger.debug(
f"Capturing CUDA graph for batch size {batch_size} ({max_seqlen_k} tokens)"
)
_g_input_ids = torch.zeros(batch_size, dtype=torch.int32, device=device)
_g_positions = torch.zeros(batch_size, dtype=torch.int64, device=device)
_g_logits = None
key_split = num_splits_heuristic(
batch_size * self.kv_manager.num_kv_heads,
max_seq_len=max_seqlen_k,
num_sms=torch.cuda.get_device_properties(device).multi_processor_count,
max_splits=12,
)
success, _g_batch_mapping = self.kv_manager.allocate_sequences(
list(range(batch_size)), [256] * batch_size
)
assert success
set_context(
is_prefill=False,
do_compression=False,
batch_mapping=_g_batch_mapping,
key_split=key_split,
)
# warmup
self.model.compute_logits(self.model(_g_input_ids, _g_positions))
dist.barrier()
decode_graph = torch.cuda.CUDAGraph()
with torch.cuda.graph(decode_graph):
_g_logits = self.model.compute_logits(
self.model(_g_input_ids, _g_positions)
)
graph_vars = {
"graph": decode_graph,
"input_ids": _g_input_ids,
"positions": _g_positions,
"batch_mapping": _g_batch_mapping,
"logits": _g_logits,
"key_split": key_split,
}
if batch_size not in self.captured_graphs:
self.captured_graphs[batch_size] = {}
self.min_captured_len[batch_size] = float("inf")
self.captured_graphs[batch_size][max_seqlen_k] = graph_vars
self.min_captured_len[batch_size] = min(
max_seqlen_k, self.min_captured_len[batch_size]
)
self.kv_manager.free_sequences(list(range(batch_size)))
def get_cuda_graph(self, batch_size: int, max_seqlen_k: int):
batch_size = next(x for x in self.captured_graphs.keys() if x >= batch_size)
batch_size_graphs = self.captured_graphs[batch_size]
# we want largest seq_len that is smaller than max_seqlen_k
best = self.min_captured_len[batch_size]
for seq_len in batch_size_graphs.keys():
if seq_len <= max_seqlen_k:
best = max(best, seq_len)
return batch_size_graphs[best]
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