Commit 2b7160c6 authored by chenzk's avatar chenzk
Browse files

vllm kvprune:v1.0.0

parent fa718036
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 vllm.kvprune.compression.common import BaseCompressionMethod
from vllm.kvprune.utils.helpers import maybe_execute_in_stream
from vllm.kvprune.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).contiguous(), PHI.contiguous())
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).contiguous(), chunk.contiguous())
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).contiguous(), chunk.contiguous())
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.contiguous(), sv.contiguous())
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 vllm.kvprune 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 ``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 vllm.kvprune.compression.common import BaseCompressionMethod
from vllm.kvprune.compression.compactor import (
CompactorCompression,
non_causal_attn_scores,
)
from vllm.kvprune.compression.snapkv import SnapKVCompression
from vllm.kvprune.utils.helpers import maybe_execute_in_stream
from vllm.kvprune.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 vllm.kvprune.compression.common import BaseCompressionMethod
from vllm.kvprune.compression.compactor import (
CompactorCompression,
kvpress_compactor_post_rope,
resolve_kvpress_compactor_blending,
)
from vllm.kvprune.compression.snapkv import SnapKVCompression
from vllm.kvprune.utils.helpers import maybe_execute_in_stream
from vllm.kvprune.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 vllm.kvprune 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 ``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 vllm.kvprune.compression.common import BaseCompressionMethod
from vllm.kvprune.compression.compactor import (
CompactorCompression,
non_causal_attn_scores,
)
from vllm.kvprune.compression.snapkv import SnapKVCompression
from vllm.kvprune.utils.helpers import maybe_execute_in_stream
from vllm.kvprune.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 vllm.kvprune 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 vllm.kvprune.compression.common import BaseCompressionMethod
from vllm.kvprune.utils.helpers import maybe_execute_in_stream
from vllm.kvprune.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 vllm.kvprune.compression.common import BaseCompressionMethod
from vllm.kvprune.utils.helpers import maybe_execute_in_stream
from vllm.kvprune.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
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""Engine / sampling / kernel constants (compactor-compatible)."""
from vllm.kvprune.config.constants import RESERVED_BATCH, TRITON_RESERVED_BATCH
__all__ = ["RESERVED_BATCH", "TRITON_RESERVED_BATCH"]
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):
"""Legacy coarse backend toggle (prefer :class:`KvpruneAttentionSchedule`)."""
FLASH_ATTENTION = auto()
COMPACTOR_TRITON = auto()
class KvpruneAttentionSchedule(Enum):
"""FlashAttention vs Triton split for prefill / decode (KV **writes** stay Triton)."""
# Default: FA varlen prefill; decode uses ``head_sparse_decode_attention`` (Triton).
FA_PREFILL_TRITON_DECODE = auto()
# Prefill attention uses ``causal_sparse_varlen_with_cache`` (Triton); decode Triton.
TRITON_PREFILL_TRITON_DECODE = auto()
# "PDFA": FA prefill + FA decode; paged KV **storage** (incl. pruned top-k) unchanged.
PDFA = 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_schedule : KvpruneAttentionSchedule, default FA_PREFILL_TRITON_DECODE
Which **attention** implementation runs on prefill vs decode. KV **writes**
(``prefill_store_*``, ``decode_store_kv``, pruned top-k) always use the
existing Triton store kernels. Env ``VLLM_KVPRUNE_ATTENTION_SCHEDULE`` uses
short names: ``fa_triton`` (default), ``pdtriton``, ``pdfa``. Enum values:
``FA_PREFILL_TRITON_DECODE`` — FA prefill, Triton decode;
``TRITON_PREFILL_TRITON_DECODE`` — Triton prefill + decode;
``PDFA`` — FA prefill + FA decode (still Triton KV I/O).
attention_backend : AttentionBackend, optional
Deprecated. Ignored if ``attention_schedule`` is set; otherwise mapped
for backward compatibility.
"""
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_schedule: KvpruneAttentionSchedule = (
KvpruneAttentionSchedule.FA_PREFILL_TRITON_DECODE
)
attention_backend: AttentionBackend | None = None
show_progress_bar: bool = True
def __post_init__(self):
if self.attention_backend is not None:
if self.attention_backend == AttentionBackend.FLASH_ATTENTION:
self.attention_schedule = KvpruneAttentionSchedule.FA_PREFILL_TRITON_DECODE
else:
self.attention_schedule = (
KvpruneAttentionSchedule.TRITON_PREFILL_TRITON_DECODE
)
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")
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""
Core: compactor ``LLMEngine`` stack (``llm_engine``, ``model_runner``, ``scheduler``, …).
v1 集成路径使用子模块显式导入(如 ``from vllm.kvprune.core.llm_engine import LLMEngine``),
不要求本包聚合已移除的可选钩子(``runtime`` / ``flash_integration`` / ``block_budget``)。
"""
from vllm.kvprune.core.compression_bridge import (
VALID_ALIASES_FOR_SAMPLING,
compression_method_id_to_enum,
compression_method_str_to_id,
)
__all__ = [
"VALID_ALIASES_FOR_SAMPLING",
"compression_method_id_to_enum",
"compression_method_str_to_id",
]
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""Map compression method strings (e.g. from :class:`~vllm.kvprune.integration.CompressionParams`) to kvprune GPU / enum IDs."""
from __future__ import annotations
from vllm.kvprune.compression.compression_config import CompressionMethod
# IDs stored on device [num_reqs_padded] (int32). Order is stable for kernels.
COMPRESSION_METHOD_ID_NONE = 0
COMPRESSION_METHOD_ID_CRITICALADAKV = 1
COMPRESSION_METHOD_ID_COMPACTOR = 2
COMPRESSION_METHOD_ID_SNAPKV = 3
# Aliases accepted for method strings (case-insensitive after strip).
VALID_ALIASES_FOR_SAMPLING: frozenset[str] = frozenset(
{"none", "criticaladakv", "compactor", "snapkv"}
)
_STR_TO_ID: dict[str, int] = {
"none": COMPRESSION_METHOD_ID_NONE,
"criticaladakv": COMPRESSION_METHOD_ID_CRITICALADAKV,
"compactor": COMPRESSION_METHOD_ID_COMPACTOR,
"snapkv": COMPRESSION_METHOD_ID_SNAPKV,
}
_ID_TO_COMPRESSION_METHOD: dict[int, CompressionMethod] = {
COMPRESSION_METHOD_ID_NONE: CompressionMethod.NONE,
COMPRESSION_METHOD_ID_CRITICALADAKV: CompressionMethod.CRITICALADAKV,
COMPRESSION_METHOD_ID_COMPACTOR: CompressionMethod.COMPACTOR,
COMPRESSION_METHOD_ID_SNAPKV: CompressionMethod.SNAPKV,
}
def compression_method_str_to_id(s: str) -> int:
"""Normalize and map user string to a stable int id (0..3)."""
key = (s or "none").strip().lower()
if key not in _STR_TO_ID:
raise ValueError(
f"Unknown compression_method {s!r}; expected one of "
f"{sorted(VALID_ALIASES_FOR_SAMPLING)}"
)
return _STR_TO_ID[key]
def compression_method_id_to_enum(method_id: int) -> CompressionMethod:
if method_id not in _ID_TO_COMPRESSION_METHOD:
return CompressionMethod.NONE
return _ID_TO_COMPRESSION_METHOD[method_id]
__all__ = [
"COMPRESSION_METHOD_ID_NONE",
"COMPRESSION_METHOD_ID_CRITICALADAKV",
"COMPRESSION_METHOD_ID_COMPACTOR",
"COMPRESSION_METHOD_ID_SNAPKV",
"VALID_ALIASES_FOR_SAMPLING",
"compression_method_id_to_enum",
"compression_method_str_to_id",
]
from __future__ import annotations
import atexit
import inspect
import logging
from pathlib import Path
from typing import Any, List, Optional, Union
import torch.nn as nn
import torch.multiprocessing as mp
from vllm.kvprune.compression.compression_config import (
BatchCompressionParams,
SequenceCompressionParams,
)
from vllm.kvprune.config.engine_config import LLMConfig
from vllm.kvprune.config.sampling_params import SamplingParams
from vllm.kvprune.core.model_runner import ModelRunner
from vllm.kvprune.models import MODEL_REGISTRY
from vllm.kvprune.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, external_model: nn.Module | None = None):
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:
# Local directory: use it directly (no Hub round-trip).
try:
mp = Path(config.model)
if mp.is_dir() and (mp / "config.json").is_file():
self.config.path = str(mp.resolve())
logger.info("Using local model directory for tokenizer: %s", self.config.path)
except OSError:
pass
if config.path is None:
from huggingface_hub import snapshot_download
# Hub repo id: allow downloading missing shards/tokenizer files when cache
# is incomplete (local_files_only=False). Local dirs are handled above.
self.config.path = snapshot_download(
repo_id=config.model,
local_files_only=False,
)
logger.info(
"Resolved Hugging Face snapshot for %s @ %s",
self.config.model,
self.config.path,
)
assert self.config.path is not None
_trust = bool(getattr(self.config.hf_config, "trust_remote_code", False))
# Always load tokenizer from the resolved on-disk tree so we do not re-hit
# the Hub with the repo id (can re-download tokenizer / LFS shards).
self.tokenizer = AutoTokenizer.from_pretrained(
self.config.path,
use_fast=True,
trust_remote_code=_trust,
)
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]
)
if external_model is not None and int(self.config.tensor_parallel_size) != 1:
raise ValueError(
"external_model (shared-weight compactor path) only supports "
"tensor_parallel_size=1"
)
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,
external_model=external_model,
)
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
import os
from typing import Iterable, List, Optional
import torch
from vllm.kvprune.config.engine_config import LLMConfig
from vllm.kvprune.kv_cache.page_table import KVAllocationStatus, PagedKVCache
from vllm.kvprune.utils.tp_utils import kv_heads_shard_divisor
from torch import nn
logger = logging.getLogger(__name__)
class KVCacheManager:
def __init__(
self,
rank: int,
config: LLMConfig,
*,
device: str | None = None,
):
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
_ws = kv_heads_shard_divisor()
self.num_kv_heads = hf_config.num_key_value_heads // _ws
assert hf_config.num_key_value_heads % _ws == 0, (
"tensor-parallel world size needs to divide num_kv_heads"
)
self._cache_device = device if device is not None else f"cuda:{self.rank}"
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=self._cache_device,
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:
# Standalone compactor: ``frac`` is a fraction of total VRAM. When a second
# engine shares the GPU with vLLM (shared weights), most VRAM is already
# committed; the formula above goes negative. Fall back to a slice of
# *currently free* memory for the compactor KV pool.
free_frac = float(
os.environ.get("VLLM_KVPRUNE_COMPACTOR_KV_FREE_FRAC", "0.55")
)
free_frac = max(0.05, min(free_frac, 0.95))
bytes_for_kv_budget = int(free * free_frac)
logger.warning(
"KV cache budget from gpu_memory_utilization (%.2f) is exhausted "
"(%.2f MiB free on device); using %.0f%% of free memory (~%.2f MiB) "
"for compactor KV (set VLLM_KVPRUNE_COMPACTOR_KV_FREE_FRAC to adjust).",
frac,
free / (1024**2),
free_frac * 100,
bytes_for_kv_budget / (1024**2),
)
if bytes_for_kv_budget <= 0:
raise RuntimeError(
"Insufficient memory for compactor KV cache: no free GPU memory left "
"after the primary vLLM engine. Lower vLLM gpu_memory_utilization or "
"max_model_len, shorten prompts, or run compactor-only / vLLM-only "
"sessions. Raising gpu_memory_utilization here does not help."
)
# 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:
# Tight VRAM: metadata alone can exceed the first budget; reserve page
# tables plus a slice of remaining free for KV tensors.
bytes_for_kv_budget = min(
int(free * 0.95),
total_page_table_bytes + max(int(free * 0.25), 8 * 1024 * 1024),
)
kv_bytes_net = bytes_for_kv_budget - total_page_table_bytes
if kv_bytes_net <= 0:
raise RuntimeError(
"page-table footprint exceeds available GPU memory for compactor KV. "
f"Reduce vLLM max_num_seqs (compactor uses {self.max_num_batches}) "
f"or max_model_len ({self.max_model_len}), or free GPU memory."
)
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
# When vLLM shares the same GPU, ``used_now`` often exceeds ``target`` (same
# situation as ``get_num_pages``), so activation_budget is ~0 and
# ``max_tokens_per_batch`` rounds to 0 or one page. The min(...) would then
# cap prefill at ~page_size tokens (e.g. 32) even though the compactor KV pool
# is large — no prompt longer than that can be scheduled. Prefer KV capacity
# (capped by max_model_len) whenever activation math yields only a token or two.
if (
max_tokens_in_cache > 0
and max_tokens_per_batch <= self.page_size
and max_tokens_in_cache > max_tokens_per_batch
):
max_tokens_per_batch = min(max_tokens_in_cache, self.max_model_len)
self.max_batched_tokens = min(max_tokens_in_cache, max_tokens_per_batch)
# Last resort: allow at least one page when KV exists but min(...) is still 0.
if self.max_batched_tokens == 0 and self.num_pages > 0 and max_tokens_in_cache > 0:
self.max_batched_tokens = min(max_tokens_in_cache, self.page_size)
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 os
import inspect
from typing import Any, List, Optional
import torch
import torch.nn as nn
import torch.distributed as dist
from vllm.kvprune.attention.sparse_decode_kernel import num_splits_heuristic
from vllm.kvprune.compression.compression_config import BatchCompressionParams
from vllm.kvprune.config.constants import RESERVED_BATCH
from vllm.kvprune.config.engine_config import LLMConfig, KvpruneAttentionSchedule
from vllm.kvprune.core.memory_manager import KVCacheManager
from vllm.kvprune.core.scheduler import Scheduler
from vllm.kvprune.layers.sampler import Sampler
from vllm.kvprune.models import MODEL_REGISTRY
from vllm.kvprune.utils.arguments import (
DecodeBatchArguments,
DecodeBatchOutput,
PackedTensorArguments,
PrefillBatchArguments,
)
from vllm.kvprune.utils.context import CompressionContext, reset_context, set_context
from vllm.kvprune.utils.kv_dist import barrier_sync, broadcast_from_tp_rank0
from vllm.kvprune.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,
external_model: Optional[nn.Module] = None,
*,
embedded_in_vllm_worker: bool = False,
device: Optional[torch.device] = None,
):
self.config = config
self.embedded_in_vllm_worker = embedded_in_vllm_worker
if embedded_in_vllm_worker:
from vllm.distributed.parallel_state import (
get_tensor_model_parallel_rank,
get_tensor_model_parallel_world_size,
)
tp_ws = get_tensor_model_parallel_world_size()
tp_rank = get_tensor_model_parallel_rank()
if tp_ws != config.tensor_parallel_size:
raise RuntimeError(
f"tensor parallel world size {tp_ws} != "
f"LLMConfig.tensor_parallel_size {config.tensor_parallel_size}"
)
self.rank = tp_rank
_dev = device if device is not None else torch.device(
f"cuda:{torch.cuda.current_device()}"
)
if not dist.is_initialized():
raise RuntimeError(
"embedded_in_vllm_worker requires torch.distributed to be "
"initialized (vLLM worker)."
)
if dist.get_world_size() != tp_ws:
raise NotImplementedError(
"KV-prune compactor embedded in vLLM currently requires "
"dist.get_world_size() == tensor_parallel_size "
"(pipeline_parallel_size=1, data_parallel_size=1). "
f"Got dist.get_world_size()={dist.get_world_size()}, "
f"tp_ws={tp_ws}."
)
else:
self.rank = rank
_dev = device if device is not None else torch.device(f"cuda:{rank}")
self._device = _dev
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
if config.attention_schedule == KvpruneAttentionSchedule.PDFA:
if not self.enforce_eager and self.rank == 0:
logger.info(
"attention_schedule=PDFA: disabling compactor decode CUDA graphs "
"(FlashAttention decode path)."
)
self.enforce_eager = True
# Embedded in vLLM worker (TP>1): respect :attr:`LLMConfig.enforce_eager` from
# ``v1_tp_runner._apply_compactor_env_overrides``. Set
# ``VLLM_KVPRUNE_TP_EMBEDDED_GRAPH=0`` to force eager if graph replay is unstable
# with shared vLLM VRAM / streams / NCCL on your stack.
if embedded_in_vllm_worker:
_tp_graph = os.environ.get(
"VLLM_KVPRUNE_TP_EMBEDDED_GRAPH", "1"
).strip().lower()
if _tp_graph in ("0", "false", "no"):
if not self.enforce_eager:
logger.info(
"embedded_in_vllm_worker: VLLM_KVPRUNE_TP_EMBEDDED_GRAPH=0 → "
"forcing compactor enforce_eager=True (skip compactor CUDA graph "
"capture)."
)
self.enforce_eager = True
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 not embedded_in_vllm_worker:
if "device_id" in inspect.signature(dist.init_process_group).parameters:
init_kwargs["device_id"] = torch.device(f"cuda:{rank}")
if not dist.is_initialized():
dist.init_process_group(
"nccl",
f"tcp://localhost:{config.nccl_port}",
world_size=self.world_size,
rank=rank,
**init_kwargs,
)
else:
ws = dist.get_world_size()
if ws != self.world_size:
raise RuntimeError(
"torch.distributed is already initialized with "
f"world_size={ws}, but compactor ModelRunner expects "
f"tensor_parallel_size={self.world_size}. "
"Use tensor_parallel_size matching the active process group "
"(typically 1 when sharing weights with vLLM)."
)
torch.cuda.set_device(_dev)
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
if external_model is not None:
self.model = external_model
else:
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)
# No paged KV yet: FA-only varlen path (see :meth:`warmup`).
self.warmup(num_warmup_tokens=self.max_model_len, with_kv=False)
post_warmup_peak = torch.cuda.memory_stats().get("allocated_bytes.all.peak", 0)
self.kv_manager = KVCacheManager(
self.rank, config, device=str(self._device)
)
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 []
# Embedded TP peers: session end is signaled via TP-group broadcast in
# maybe_release_peers (no multiprocessing.Event — not pickleable over RPC).
self._embedded_peer_continue = True
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}")
self.warmup(num_warmup_tokens=self.max_model_len, with_kv=True)
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)
if not self.captured_graphs:
logger.warning(
"No compactor CUDA graphs were captured (KV budget tight or "
"allocate_sequences failed during capture). Using eager decode "
"for this session."
)
self.enforce_eager = True
self.packed_args = PackedTensorArguments(
rank=self.rank,
max_batched_tokens=self.max_batched_tokens,
config=self.config,
device=self._device,
use_tp_group_for_collectives=embedded_in_vllm_worker,
)
atexit.register(self.exit)
@torch.inference_mode()
def warmup(self, num_warmup_tokens: int, *, with_kv: bool):
sched = (
self.config.attention_schedule
if with_kv
else KvpruneAttentionSchedule.FA_PREFILL_TRITON_DECODE
)
if self.rank == 0:
logger.info(
"Warming up compactor attention (%s KV init): schedule=%s",
"after" if with_kv else "before",
sched.name,
)
device = self._device
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 with_kv:
success, batch_mapping = self.kv_manager.allocate_sequences(
[-1], [num_warmup_tokens]
)
assert success
max_bh_len = int(
self.kv_manager.paged_cache.bh_seq_lens.index_select(
1, index=batch_mapping
)
.max()
.item()
)
else:
batch_mapping = None
max_bh_len = 0
set_context(
is_prefill=True,
do_compression=False,
cu_seqlens_q=cu_seqlens_q,
cu_seqlens_k=cu_seqlens_k,
cu_seqlens_q_host=(0, num_warmup_tokens),
cu_seqlens_k_host=(0, num_warmup_tokens),
max_seqlen_q=num_warmup_tokens,
max_seqlen_k=num_warmup_tokens,
batch_mapping=batch_mapping,
max_bh_len=max_bh_len,
attention_schedule=sched,
)
for _ in range(2):
torch.cuda.reset_peak_memory_stats()
h = self.model(input_ids, positions)
self.model.compute_logits(h)
barrier_sync(use_tp_group=self.embedded_in_vllm_worker)
if with_kv:
self.kv_manager.paged_cache.bh_seq_lens.index_fill_(
1, batch_mapping.to(torch.long), 0
)
reset_context()
if with_kv:
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 getattr(self, "embedded_in_vllm_worker", False):
return
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,
)
cu_q_host = tuple(
int(x) for x in prefill_args.cu_seqlens_q.detach().cpu().view(-1).tolist()
)
cu_k_host = tuple(
int(x) for x in prefill_args.cu_seqlens_k.detach().cpu().view(-1).tolist()
)
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,
cu_seqlens_q_host=cu_q_host,
cu_seqlens_k_host=cu_k_host,
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_schedule=self.config.attention_schedule,
)
# int32 token ids break vLLM-delegated embedding (expects long indices) on some paths.
_iid = (
prefill_args.input_ids
if prefill_args.input_ids.dtype == torch.int64
else prefill_args.input_ids.long()
)
_pos = (
prefill_args.positions
if prefill_args.positions.dtype == torch.int64
else prefill_args.positions.long()
)
hidden = self.model(_iid, _pos)
logits = self.model.compute_logits(hidden)
reset_context()
return logits
def maybe_broadcast(self, tensor: torch.Tensor, *, label: str = "tensor") -> None:
if self.world_size > 1:
broadcast_from_tp_rank0(
tensor, use_tp_group=self.embedded_in_vllm_worker
)
return None
def maybe_release_peers(self, do_release=False):
if self.world_size <= 1:
return
if self.embedded_in_vllm_worker:
flag = torch.zeros(1, dtype=torch.int32, device=self._device)
if self.is_master:
flag[0] = 0 if do_release else 1
broadcast_from_tp_rank0(flag, use_tp_group=True)
if not self.is_master:
self._embedded_peer_continue = bool(flag[0].item())
barrier_sync(use_tp_group=True)
return
if self.is_master:
if do_release:
for event in self.peer_events:
event.clear()
barrier_sync(use_tp_group=False)
else:
barrier_sync(use_tp_group=False)
def _peer_outer_loop_active(self) -> bool:
if self.batch_ready is not None:
return self.batch_ready.is_set()
if self.embedded_in_vllm_worker:
return self._embedded_peer_continue
return False
@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"
if not self.embedded_in_vllm_worker:
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=self._device)
while not scheduler.is_finished():
sequences = scheduler.get_prefill_batch()
if not sequences:
if scheduler.pending_sequence_ids:
raise RuntimeError(
"KV-prune compactor cannot schedule any prefill (KV/token budget). "
f"max_batched_tokens={self.kv_manager.max_batched_tokens}, "
f"pending_sequences={len(scheduler.pending_sequence_ids)}. "
"Lower v1 gpu_memory_utilization / max_model_len, set "
"VLLM_KVPRUNE_RELEASE_V1_KV=1 to discard v1 KV (sleep+wake), "
"or free GPU memory. Diagnostics: "
f"{scheduler.diagnose_prefill_failure()}"
)
# Pending is empty: either finished or decode-only continuation.
if decode_batch.token_ids is None:
break
run_decode = True
occupancy = -1
else:
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,
).to(device=self._device, 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, label="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 run_peer_session(self) -> None:
"""Non-master TP ranks: run one peer session (used when embedded in vLLM)."""
if self.embedded_in_vllm_worker:
self._embedded_peer_continue = True
self._process_batches_peer()
@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=self._device)
while self._peer_outer_loop_active():
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, label="decode_flags")
run_decode = bool(decode_flags[0].item())
occupancy = int(decode_flags[1].item())
token_ids = torch.empty(B, dtype=torch.int64, device=self._device)
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, label="decode_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
logits = self._decode_step_logits(decode_batch)
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
def _decode_logits_eager(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
batch_mapping: torch.Tensor,
):
set_context(
is_prefill=False,
do_compression=False,
batch_mapping=batch_mapping,
attention_schedule=self.config.attention_schedule,
)
_iid = input_ids if input_ids.dtype == torch.int64 else input_ids.long()
_pos = positions if positions.dtype == torch.int64 else positions.long()
hidden = self.model(_iid, _pos)
return self.model.compute_logits(hidden)
@torch.inference_mode()
def _decode_step_logits(self, decode_batch: DecodeBatchArguments):
"""Graph decode when possible; otherwise eager (never raises on missing graph)."""
if self.enforce_eager or not self.captured_graphs:
return self._decode_logits_eager(
decode_batch.token_ids,
decode_batch.positions,
decode_batch.batch_mapping,
)
try:
return self.run_graph_decode(
decode_batch.token_ids,
decode_batch.positions,
decode_batch.batch_mapping,
)
except Exception as e:
logger.warning(
"CUDA graph decode failed (%s); switching to eager decode for "
"remaining steps.",
e,
)
self.enforce_eager = True
return self._decode_logits_eager(
decode_batch.token_ids,
decode_batch.positions,
decode_batch.batch_mapping,
)
@torch.inference_mode()
def run_graph_decode(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
batch_mapping: torch.Tensor,
):
bs = input_ids.shape[0]
max_k = int(positions.max())
graph_dict = self.get_cuda_graph(bs, max_k)
if graph_dict is None:
return self._decode_logits_eager(input_ids, positions, batch_mapping)
set_context(
is_prefill=False,
do_compression=False,
batch_mapping=batch_mapping,
attention_schedule=self.config.attention_schedule,
)
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()
logits_out = graph_dict["logits"]
return logits_out[:bs].contiguous()
@torch.inference_mode()
def capture_cudagraph(self, batch_size: int, max_seqlen_k: int):
barrier_sync(use_tp_group=self.embedded_in_vllm_worker)
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_hidden = 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
)
if not success:
# Shared GPU with vLLM: compactor KV pool is small; large batch capture
# often cannot reserve [256]*batch_size per sequence. Skip this graph.
logger.warning(
"Skipping CUDA graph capture for batch_size=%s max_seqlen_k=%s "
"(KV allocate_sequences failed; decode will use eager or other graphs).",
batch_size,
max_seqlen_k,
)
barrier_sync(use_tp_group=self.embedded_in_vllm_worker)
return
set_context(
is_prefill=False,
do_compression=False,
batch_mapping=_g_batch_mapping,
key_split=key_split,
attention_schedule=self.config.attention_schedule,
)
_gw = self.model(_g_input_ids, _g_positions)
self.model.compute_logits(_gw)
barrier_sync(use_tp_group=self.embedded_in_vllm_worker)
decode_graph = torch.cuda.CUDAGraph()
with torch.cuda.graph(decode_graph):
_g_hidden = self.model(_g_input_ids, _g_positions)
_g_logits = self.model.compute_logits(_g_hidden)
graph_vars = {
"graph": decode_graph,
"input_ids": _g_input_ids,
"positions": _g_positions,
"batch_mapping": _g_batch_mapping,
"hidden": _g_hidden,
"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
) -> Optional[dict[str, Any]]:
"""Return a captured graph dict, or None if no compatible capture exists."""
if not self.captured_graphs:
return None
eligible_bs = [x for x in self.captured_graphs.keys() if x >= batch_size]
if not eligible_bs:
return None
bs_key = min(eligible_bs)
batch_size_graphs = self.captured_graphs[bs_key]
candidates = [sl for sl in batch_size_graphs.keys() if sl <= max_seqlen_k]
if not candidates:
return None
best_sl = max(candidates)
return batch_size_graphs[best_sl]
import time
from typing import Iterable, List
from vllm.kvprune.core.memory_manager import KVCacheManager
from vllm.kvprune.utils.sequence import Sequence, SequenceStatus
from tqdm import tqdm
def cdiv(a, b):
"""ceiling division"""
return (a + b - 1) // b
class Scheduler:
"""
Simple sequence scheduler for prefill + decode with a paged KV cache.
The scheduler tracks three disjoint sets of sequence IDs:
* ``pending_sequence_ids`` 鈥?sequences that have not yet been started.
* ``active_sequence_ids`` 鈥?sequences currently running.
* ``finished_sequence_ids`` 鈥?sequences that have generated all tokens.
At prefill time, :meth:`get_prefill_batch` selects a subset of pending
sequences that can fit into the available KV cache and per-step token
budget, given the constraints from the associated :class:`KVCacheManager`.
The class also handles basic bookkeeping of sequence statuses.
Args:
:param all_sequences:
Iterable of :class:`Sequence` objects to be scheduled. Each
sequence must have a unique ``seq_id``.
:param kv_manager:
A :class:`KVCacheManager` instance that this scheduler will use
to determine whether additional batches can be scheduled.
:param use_tqdm:
If True, two progress bars are created:
* "Started Batches" 鈥?increments when a sequence moves from
pending to running.
* "Finished Batches" 鈥?increments when a sequence finishes.
"""
def __init__(
self,
all_sequences: Iterable[Sequence],
kv_manager: KVCacheManager,
*,
use_tqdm=False,
):
self.allseq_mapping: dict[int, Sequence] = {s.seq_id: s for s in all_sequences}
self.pending_sequence_ids: set[int] = set([s.seq_id for s in all_sequences])
self.active_sequence_ids: set[int] = set()
self.finished_sequence_ids: set[int] = set()
self.manager = kv_manager
self.use_tqdm = use_tqdm
self.start_time = time.perf_counter()
self.total_tokens_generated = 0
self.total_tokens_input = 0
self.pbar = None
if use_tqdm:
self.pbar = tqdm(
total=len(self.pending_sequence_ids),
desc="Completed Batches",
)
def get_prefill_batch(self) -> List[Sequence]:
"""
Select a batch of pending sequences to prefill under KV/memory constraints.
The selection is greedy over ``pending_sequence_ids`` in iteration order.
A sequence is added to the batch if:
* The sum of its prompt length and the total prompt tokens selected so
far does not exceed ``manager.max_batched_tokens``, and
* There is at least one free KV "batch slot" left
(``manager.num_free_batches``), and
* The total number of KV pages required by the sequence's prompt +
max_new_tokens does not exceed the remaining free pages.
Returns:
:return List[Sequence]:
The list of :class:`Sequence` objects chosen for prefill in
this step. The caller is responsible for marking them as
active via :meth:`add_running_sequence_ids`.
"""
total_tok, sequences = 0, []
num_free_batches, num_free_pages = (
self.manager.num_free_batches,
self.manager.num_free_pages,
)
for seq_id in self.pending_sequence_ids:
seq = self.allseq_mapping[seq_id]
prompt_length = seq.prompt_len
pages_needed = (
cdiv(
prompt_length + seq.sampling_params.max_new_tokens,
self.manager.page_size,
)
* self.manager.num_kv_heads
)
if (
prompt_length + total_tok <= self.manager.max_batched_tokens
and num_free_batches > 0
and pages_needed < num_free_pages
):
sequences.append(seq)
total_tok += prompt_length
num_free_pages -= pages_needed
num_free_batches -= 1
return sequences
def is_finished(self) -> bool:
"""
Check whether all sequences have completed.
"""
return (
len(self.pending_sequence_ids) == 0 and len(self.active_sequence_ids) == 0
)
def any_pending_sequences(self) -> bool:
"""
Check whether any sequences are still pending (not yet started).
"""
return len(self.pending_sequence_ids) != 0
def add_running_sequence_ids(
self, active_sequence_ids: Iterable[int], *, update_status: bool = False
):
"""
Mark a set of sequences as active / running. This moves sequence IDs
from ``pending_sequence_ids`` into ``active_sequence_ids``. Optionally,
it also updates the per-sequence status and progress bar.
Args:
:param active_sequence_ids:
Iterable of sequence IDs that have been scheduled for prefill
or decode and should now be considered running.
:param update_status:
If True, set each corresponding :class:`Sequence`'s
``status = SequenceStatus.RUNNING`` and increment the
"Started Batches" progress bar if ``use_tqdm`` is enabled.
"""
self.active_sequence_ids.update(active_sequence_ids)
self.pending_sequence_ids.difference_update(self.active_sequence_ids)
if update_status:
for seq_id in active_sequence_ids:
self.allseq_mapping[seq_id].status = SequenceStatus.RUNNING
self.total_tokens_input += self.allseq_mapping[seq_id].prompt_len
def get_finished_sequence_ids_from_unfinished(
self, unfinished_sequence_ids: Iterable[int]
) -> set[int]:
"""
Infer which active sequences have finished given the
unfinished set (for decode steps where the caller knows
which sequences are still generating but not necessarily
which have just completed).
Args:
:param unfinished_sequence_ids:
Iterable of sequence IDs that are still running
Returns:
:return set[int]:
The inferred set of sequence IDs that transitioned from active
to finished.
"""
return self.active_sequence_ids.difference(unfinished_sequence_ids)
def record_finished_sequence_ids(
self, finished_sequence_ids: Iterable[int], *, update_status: bool = False
):
"""
Record that a set of sequences has finished generation.
This moves IDs from ``active_sequence_ids`` into
``finished_sequence_ids``.
Args:
:param finished_sequence_ids:
Iterable of sequence IDs that have completed generation and
no longer require KV cache.
:param update_status:
If True, set each corresponding :class:`Sequence`'s
``status = SequenceStatus.FINISHED``
"""
self.active_sequence_ids.difference_update(finished_sequence_ids)
self.finished_sequence_ids.update(finished_sequence_ids)
if update_status:
for seq_id in finished_sequence_ids:
self.allseq_mapping[seq_id].status = SequenceStatus.FINISHED
if self.pbar is not None:
self.pbar.update(1)
def update_sequences(self, tokens: Iterable[int], seq_ids: Iterable[int]):
"""
Append newly generated tokens to their corresponding sequences.
Args:
:param tokens:
Iterable of generated token IDs, one per sequence.
:param seq_ids:
Iterable of sequence IDs aligned with ``tokens``.
"""
cur_time = time.perf_counter()
for tok, seq_id in zip(tokens, seq_ids):
self.allseq_mapping[seq_id].add_new_token(tok)
self.total_tokens_generated += 1
if self.pbar is not None:
self.pbar.set_description(
f"Throughput: {(self.total_tokens_generated + self.total_tokens_input) / (cur_time - self.start_time):.2f} tok/s"
)
def close(self):
if self.pbar is not None:
self.pbar.close()
def can_prefill_another_batch(self) -> bool:
return len(self.get_prefill_batch()) > 0
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""KV-pruning integration: compactor ``LLMEngine`` sharing weights with :class:`~vllm.LLM`."""
from vllm.kvprune.integration.compression_params import CompressionParams
__all__ = ["CompressionParams"]
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""Construct compactor :class:`LLMEngine` sharing weight tensors with an in-process vLLM ``LLM``."""
from __future__ import annotations
import os
import torch.nn as nn
from vllm.config import VllmConfig
from vllm.kvprune.config.engine_config import LLMConfig
from vllm.kvprune.core.llm_engine import LLMEngine
from vllm.kvprune.integration.config_adapter import vllm_config_to_llm_config
from vllm.kvprune.integration.vllm_model_access import extract_vllm_causal_lm
from vllm.kvprune.integration.weight_tie import (
delegate_kvprune_compute_logits_to_vllm,
delegate_kvprune_embed_tokens_to_vllm,
tie_kvprune_rope_buffers_from_vllm,
tie_kvprune_weights_from_vllm,
)
from vllm.kvprune.models import MODEL_REGISTRY
from vllm.logger import init_logger
logger = init_logger(__name__)
def build_llm_config_for_compactor(vc: VllmConfig) -> LLMConfig:
"""Public helper: vLLM config → compactor :class:`LLMConfig`."""
return vllm_config_to_llm_config(vc)
def create_compactor_engine_with_shared_weights(llm: object) -> LLMEngine:
"""Single GPU, TP=1: compactor ``LLMEngine`` whose weights alias vLLM tensors.
Call after the vLLM ``LLM`` has loaded weights. Requires in-process executor
(``VLLM_ENABLE_V1_MULTIPROCESSING=0``).
"""
llm_engine = getattr(llm, "llm_engine", None)
if llm_engine is None:
raise RuntimeError("Expected ``llm.llm_engine``.")
vc: VllmConfig = llm_engine.vllm_config
if vc.parallel_config.tensor_parallel_size != 1:
raise ValueError(
"Shared-weight compactor backend requires tensor_parallel_size=1"
)
cfg = vllm_config_to_llm_config(vc)
# ``cfg.enforce_eager`` is for the compactor ``ModelRunner`` only (decode CUDA
# graphs), not v1. v1 graph capture is controlled solely by ``LLM(...,
# enforce_eager=...)`` / ``kvprune_compression=True`` on the entrypoint ``LLM``.
# Large vLLM max_num_seqs blows up compactor page-table GPU memory; sharing the GPU
# with v1 leaves little room for metadata + KV tensors. Default cap 32 so physical
# KV pages stay usable; set VLLM_KVPRUNE_COMPACTOR_MAX_NUM_SEQS=0 to disable cap,
# or raise (e.g. 128) if you have VRAM headroom.
_cap = os.environ.get("VLLM_KVPRUNE_COMPACTOR_MAX_NUM_SEQS", "32").strip()
if _cap:
lim = int(_cap)
if lim > 0:
cfg.max_num_seqs = min(cfg.max_num_seqs, lim)
# Compactor decode graphs (``enforce_eager=False``): honored for non-shared-weight
# engines. **Shared-weight** path (below) forces ``enforce_eager=True`` after
# delegating ``compute_logits`` to vLLM unless ``VLLM_KVPRUNE_SHARED_WEIGHT_GRAPH=1``.
# Opt out of graphs for non-shared runs: ``VLLM_KVPRUNE_COMPACTOR_ENFORCE_EAGER=1`` or
# ``VLLM_KVPRUNE_COMPACTOR_CUDA_GRAPH=0``.
_ce = os.environ.get("VLLM_KVPRUNE_COMPACTOR_ENFORCE_EAGER", "").strip().lower()
if _ce in ("1", "true", "yes"):
cfg.enforce_eager = True
logger.info(
"KV-prune compactor: VLLM_KVPRUNE_COMPACTOR_ENFORCE_EAGER=1 → "
"enforce_eager=True (skip compactor decode CUDA graphs)."
)
elif _ce in ("0", "false", "no"):
cfg.enforce_eager = False
logger.info(
"KV-prune compactor: VLLM_KVPRUNE_COMPACTOR_ENFORCE_EAGER=0 → "
"enforce_eager=False (try compactor CUDA graph capture)."
)
else:
_dg = os.environ.get(
"VLLM_KVPRUNE_COMPACTOR_CUDA_GRAPH", "1"
).strip().lower()
if _dg in ("0", "false", "no"):
cfg.enforce_eager = True
logger.info(
"KV-prune compactor: VLLM_KVPRUNE_COMPACTOR_CUDA_GRAPH=0 → "
"enforce_eager=True (skip compactor decode CUDA graphs)."
)
else:
cfg.enforce_eager = False
logger.info(
"KV-prune compactor: default try decode CUDA graphs; ModelRunner "
"falls back to eager if capture yields none. Set "
"VLLM_KVPRUNE_COMPACTOR_ENFORCE_EAGER=1 or "
"VLLM_KVPRUNE_COMPACTOR_CUDA_GRAPH=0 to skip capture."
)
hf = cfg.hf_config
assert hf is not None
model_type = hf.model_type
if model_type not in MODEL_REGISTRY:
raise ValueError(
f"Compactor MODEL_REGISTRY has no entry for model_type={model_type!r}; "
f"supported: {sorted(MODEL_REGISTRY)}"
)
vllm_model = extract_vllm_causal_lm(llm)
device = next(vllm_model.parameters()).device
dtype = next(vllm_model.parameters()).dtype
# Build compactor shell on CPU first. **Do not** call ``.to(device)`` before tying:
# that allocates a full second copy of weights on GPU; tying then frees the
# duplicate but peak memory can OOM on large models. Tie first so parameters
# alias vLLM tensors directly (no extra weight VRAM).
kv_model: nn.Module = MODEL_REGISTRY[model_type](hf)
tie_kvprune_weights_from_vllm(vllm_model, kv_model)
# Buffers (e.g. RoPE tables) not in ``named_parameters`` may still be on CPU.
kv_model.to(device=device, dtype=dtype)
tie_kvprune_rope_buffers_from_vllm(vllm_model, kv_model)
delegate_kvprune_embed_tokens_to_vllm(vllm_model, kv_model)
delegate_kvprune_compute_logits_to_vllm(vllm_model, kv_model)
# Compactor decode CUDA graphs capture ``model.forward`` + ``compute_logits`` in one
# graph. Here ``compute_logits`` is delegated to vLLM's LM head / LogitsProcessor
# (cublas GEMM, padded vocab, etc.). Embedding that in a nested capture commonly
# fails with ``CUBLAS_STATUS_EXECUTION_FAILED`` and invalidates stream capture
# (``cudaErrorStreamCaptureInvalidated``). Default: skip graphs for this integration.
_sw_graph = os.environ.get(
"VLLM_KVPRUNE_SHARED_WEIGHT_GRAPH", "0"
).strip().lower() in ("1", "true", "yes")
if not _sw_graph:
cfg.enforce_eager = True
logger.info(
"KV-prune shared-weight compactor: enforce_eager=True (skip compactor "
"decode CUDA graphs; logits delegated to vLLM). Set "
"VLLM_KVPRUNE_SHARED_WEIGHT_GRAPH=1 only to attempt capture (often fails)."
)
return LLMEngine(cfg, external_model=kv_model)
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""KV-pruning (compactor) path invoked from :meth:`vllm.entrypoints.llm.LLM.generate`."""
from __future__ import annotations
import os
from collections.abc import Callable, Sequence
from pathlib import Path
from typing import Any
from tqdm.auto import tqdm
from transformers import AutoTokenizer
from vllm.kvprune.compression.compression_config import (
BatchCompressionParams,
SequenceCompressionParams,
)
from vllm.kvprune.config.sampling_params import SamplingParams as CompactorSamplingParams
from vllm.kvprune.core.compression_bridge import (
compression_method_id_to_enum,
compression_method_str_to_id,
)
from vllm.kvprune.core.llm_engine import LLMEngine, _infer_stop_token_ids
from vllm.kvprune.integration.compactor_shared import create_compactor_engine_with_shared_weights
from vllm.kvprune.integration.compression_params import CompressionParams
from vllm.logger import init_logger
from vllm.outputs import CompletionOutput, RequestOutput
from vllm.sampling_params import SamplingParams
logger = init_logger(__name__)
_MP_ENV = "VLLM_ENABLE_V1_MULTIPROCESSING"
_RELEASE_V1_KV_ENV = "VLLM_KVPRUNE_RELEASE_V1_KV"
def _maybe_release_v1_kv_for_compactor(llm: Any) -> None:
"""Optionally discard v1's KV cache so more GPU memory is free for compactor.
v1 reserves KV blocks at engine init; shared-weight compactor then competes for
the same VRAM. ``sleep(level=1)`` discards v1 KV and may offload tagged weights
per v1 sleep policy, then ``wake_up()`` reloads — compactor still ties the same
v1 tensors after.
**Default:** ``vllm.env_override`` sets ``VLLM_KVPRUNE_RELEASE_V1_KV=0`` (no
sleep/wake; v1 KV stays on GPU). Set ``=1`` if you need extra VRAM for compactor
before the first compressed step (then ``llm.sleep`` / ``CuMemAllocator`` /
``Sleep mode freed …`` logs are expected). This does **not** remove v1's KV
reservation at init; it only runs the optional sleep/wake cycle before compactor.
Tests keep ``VLLM_KVPRUNE_RELEASE_V1_KV=0`` in ``conftest``.
"""
if os.environ.get(_RELEASE_V1_KV_ENV, "0").strip().lower() not in (
"1",
"true",
"yes",
):
return
try:
logger.info(
"%s=1: discarding v1 KV via sleep(level=1) then wake_up() "
"(reloads model weights to GPU).",
_RELEASE_V1_KV_ENV,
)
llm.sleep(level=1, mode="abort")
llm.wake_up()
except Exception as e:
logger.warning("%s: sleep/wake failed: %s", _RELEASE_V1_KV_ENV, e)
def ensure_inprocess_engine_for_weight_sharing() -> None:
"""Compactor must see ``worker.get_model()`` in the same process as vLLM."""
if os.environ.get(_MP_ENV, "1") != "0":
os.environ[_MP_ENV] = "0"
logger.info(
"KV cache pruning: set %s=0 so the model stays in-process for "
"shared-weight compactor (no manual env needed).",
_MP_ENV,
)
def _normalize_prompt_list(prompts: Any) -> list[Any]:
if isinstance(prompts, str):
return [prompts]
if isinstance(prompts, dict):
return [prompts]
return list(prompts)
def _normalize_sampling_params(
sampling_params: SamplingParams | Sequence[SamplingParams] | None,
n: int,
) -> list[SamplingParams]:
if sampling_params is None:
return [SamplingParams() for _ in range(n)]
if isinstance(sampling_params, SamplingParams):
return [sampling_params] * n
sps = list(sampling_params)
if len(sps) != n:
raise ValueError(
f"sampling_params length {len(sps)} != prompts length {n}"
)
return sps
def _normalize_compression_params(
compression: CompressionParams | Sequence[CompressionParams] | None,
n: int,
) -> list[CompressionParams]:
if compression is None:
return [CompressionParams(compression_ratio=1.0) for _ in range(n)]
if isinstance(compression, CompressionParams):
return [compression] * n
comp = list(compression)
if len(comp) != n:
raise ValueError(f"compression length {len(comp)} != prompts length {n}")
return comp
def _any_compactor(comps: list[CompressionParams]) -> bool:
return any(c.compression_ratio < 1.0 for c in comps)
_FORCE_COMPACTOR_PATH_ENV = "VLLM_KVPRUNE_FORCE_COMPACTOR_PATH"
def _should_use_kvprune_compactor_path(comps: list[CompressionParams]) -> bool:
"""Use integrated compactor when any prompt requests compression, or when forced.
If all ``compression_ratio >= 1.0``, the default is to return ``None`` from
:func:`try_compressed_generate` and fall back to the standard v1 engine
(``Processed prompts`` loop). That hides TP/kvprune bugs behind a different
code path. Set ``VLLM_KVPRUNE_FORCE_COMPACTOR_PATH=1`` to run the same
compactor + collective RPC path as compression-on, with no KV pruning.
"""
if _any_compactor(comps):
return True
return os.environ.get(_FORCE_COMPACTOR_PATH_ENV, "").strip().lower() in (
"1",
"true",
"yes",
)
def _to_compactor_sampling(sp: SamplingParams) -> CompactorSamplingParams:
mt = sp.max_tokens
if mt is None:
mt = 16
return CompactorSamplingParams(
temperature=float(sp.temperature),
max_new_tokens=int(mt),
)
def _to_sequence_compression(cp: CompressionParams) -> SequenceCompressionParams:
return SequenceCompressionParams(
compression_ratio=float(cp.compression_ratio),
protected_first_tokens=int(cp.protected_first_tokens),
protected_last_tokens=int(cp.protected_last_tokens),
)
def _batch_compression_from_comps(comps: list[CompressionParams]) -> BatchCompressionParams:
for c in comps:
if c.compression_ratio < 1.0:
mid = compression_method_str_to_id(c.compression_method)
return BatchCompressionParams(
compression_method=compression_method_id_to_enum(mid)
)
return BatchCompressionParams()
def _kvprune_compactor_hf_tokenizer(llm: Any):
"""HF tokenizer matching :meth:`vllm.kvprune.core.llm_engine.LLMEngine.__init__`.
Loads from the **resolved on-disk** model tree (local dir or HF cache snapshot), not
the bare repo id, to avoid redundant Hub downloads.
"""
cached = getattr(llm, "_kvprune_compactor_hf_tokenizer", None)
if cached is not None:
return cached
mc = llm.llm_engine.vllm_config.model_config
model_s = str(mc.model)
src = model_s
try:
p = Path(model_s)
if p.is_dir() and (p / "config.json").is_file():
src = str(p.resolve())
else:
from huggingface_hub import snapshot_download
src = snapshot_download(repo_id=model_s, local_files_only=False)
except Exception:
src = model_s
hf_cfg = mc.hf_config
_trust = bool(getattr(hf_cfg, "trust_remote_code", False)) if hf_cfg is not None else False
tok = AutoTokenizer.from_pretrained(src, use_fast=True, trust_remote_code=_trust)
llm._kvprune_compactor_hf_tokenizer = tok
return tok
def _prompt_to_compactor_input(prompt: Any) -> str | list[int]:
if isinstance(prompt, str):
return prompt
# Decoder-only `list[int]` token ids (see `vllm.inputs.PromptType`).
if isinstance(prompt, list):
if not prompt:
raise TypeError("Empty token-id prompt is not supported for compactor path.")
if all(isinstance(t, int) for t in prompt):
return list(prompt)
if isinstance(prompt, dict):
if "prompt_token_ids" in prompt:
ids = prompt["prompt_token_ids"]
return list(ids) if not isinstance(ids, list) else ids
p = prompt.get("prompt")
if isinstance(p, str):
return p
raise TypeError(
f"Unsupported prompt type for compactor path: {type(prompt)}. "
"Use str, list[int] token ids, or dict with 'prompt_token_ids' or 'prompt'."
)
def _prompt_to_token_ids_for_tp(llm: Any, prompt: Any) -> list[int]:
"""Driver-side token ids for the TP collective path (same tokenizer as vLLM ``LLM``)."""
comp_in = _prompt_to_compactor_input(prompt)
if isinstance(comp_in, str):
return llm.get_tokenizer().encode(comp_in)
return list(comp_in)
def _compressed_generate_tp_collective(
llm: Any,
plist: list[Any],
sps: list[SamplingParams],
comps: list[CompressionParams],
) -> list[RequestOutput]:
"""TP>1: run compactor on each worker via ``collective_rpc`` (all ranks)."""
vc = llm.llm_engine.vllm_config
pc = vc.parallel_config
if pc.pipeline_parallel_size != 1 or pc.data_parallel_size != 1:
raise NotImplementedError(
"KV-prune TP compression requires pipeline_parallel_size=1 and "
f"data_parallel_size=1 (got PP={pc.pipeline_parallel_size}, "
f"DP={pc.data_parallel_size})."
)
hf = vc.model_config.hf_config
tok = llm.get_tokenizer()
eos_token_ids = _infer_stop_token_ids(tok, hf)
prompt_token_ids = [_prompt_to_token_ids_for_tp(llm, p) for p in plist]
max_len = int(vc.model_config.max_model_len)
for i, ids in enumerate(prompt_token_ids):
if len(ids) > max_len:
raise ValueError(
f"KV-prune TP compressed generate: prompt {i} length {len(ids)} "
f"exceeds max_model_len ({max_len}). Shorten the prompt or raise "
"max_model_len when constructing LLM()."
)
# Payload must be picklable for multiproc/Ray RPC: do not pass multiprocessing
# synchronization primitives (workers are separate processes).
payload: dict[str, Any] = {
"eos_token_ids": eos_token_ids,
"prompt_token_ids": prompt_token_ids,
"sampling_params": [
{
"temperature": float(sp.temperature),
"max_new_tokens": int(sp.max_tokens if sp.max_tokens is not None else 16),
}
for sp in sps
],
"compression_params": [
{
"compression_ratio": float(c.compression_ratio),
"compression_method": str(c.compression_method),
"protected_first_tokens": int(c.protected_first_tokens),
"protected_last_tokens": int(c.protected_last_tokens),
}
for c in comps
],
}
_maybe_release_v1_kv_for_compactor(llm)
try:
results = llm.llm_engine.collective_rpc(
"kvprune_v1_compressed_generate",
args=(payload,),
)
except RuntimeError as e:
if "cancelled" in str(e).lower():
raise RuntimeError(
"collective_rpc was cancelled (a GPU worker likely crashed). "
"Scroll up for the first worker traceback — often NCCL/CUDA before "
"TCPStore/Broken pipe on the driver."
) from e
raise
master: dict[str, Any] | None = None
for r in results:
if isinstance(r, dict) and r.get("tensor_parallel_rank") == 0:
master = r
break
if master is None:
raise RuntimeError(
"collective_rpc did not return a dict from tensor parallel rank 0."
)
return _tp_payload_to_request_outputs(llm, master)
def _tp_payload_to_request_outputs(llm: Any, master: dict[str, Any]) -> list[RequestOutput]:
tok = llm.get_tokenizer()
out: list[RequestOutput] = []
pids_list = master["prompt_token_ids"]
cids_list = master["completion_token_ids"]
for i, (pids, cids) in enumerate(zip(pids_list, cids_list)):
text = tok.decode(cids, skip_special_tokens=True)
# Match ``_sequences_to_request_outputs``: if decode is only special tokens,
# skip_special_tokens=True yields blank text while token list is non-empty.
if not text.strip() and cids:
text = tok.decode(cids, skip_special_tokens=False)
co = CompletionOutput(
index=0,
text=text,
token_ids=list(cids),
cumulative_logprob=None,
logprobs=None,
finish_reason="stop",
)
ro = RequestOutput(
request_id=f"kvprune-tp-{i}",
prompt=None,
prompt_token_ids=list(pids),
prompt_logprobs=None,
outputs=[co],
finished=True,
)
out.append(ro)
return out
def _ensure_compactor_engine(llm: Any) -> LLMEngine:
if llm._kvprune_compactor_engine is None:
pc = llm.llm_engine.vllm_config.parallel_config
if pc.tensor_parallel_size != 1:
raise ValueError(
"KV-pruning compactor path requires tensor_parallel_size=1 "
"for shared weights."
)
llm._kvprune_compactor_engine = create_compactor_engine_with_shared_weights(llm)
logger.info("Initialized compactor LLMEngine with weights shared from vLLM.")
return llm._kvprune_compactor_engine
def try_compressed_generate(
llm: Any,
prompts: Any,
sampling_params: SamplingParams | Sequence[SamplingParams] | None,
*,
compression: CompressionParams | Sequence[CompressionParams] | None,
use_tqdm: bool | Callable[..., tqdm] = True,
lora_request: Any = None,
priority: list[int] | None = None,
tokenization_kwargs: dict[str, Any] | None = None,
) -> list[RequestOutput] | None:
"""Return completions on the compactor engine, or ``None`` to use normal v1.
``lora_request`` / ``priority`` / ``tokenization_kwargs`` are accepted for API
parity with :meth:`~vllm.entrypoints.llm.LLM.generate` but are not passed to the
compactor engine yet.
"""
del lora_request, priority, tokenization_kwargs, use_tqdm
plist = _normalize_prompt_list(prompts)
sps = _normalize_sampling_params(sampling_params, len(plist))
comps = _normalize_compression_params(compression, len(plist))
pc = llm.llm_engine.vllm_config.parallel_config
# TP>1: every worker must run the same collective_rpc session. If all
# compression_ratio >= 1, the old code returned None and only the driver ran
# v1 _run_engine — other ranks never joined a matching collective, which can
# deadlock NCCL / leave workers unsynchronized (hang at "Processed prompts:").
if pc.tensor_parallel_size > 1:
if not _should_use_kvprune_compactor_path(comps):
comps = [CompressionParams(compression_ratio=1.0) for _ in plist]
elif not _should_use_kvprune_compactor_path(comps):
return None
v1_eager = bool(
getattr(llm.llm_engine.vllm_config.model_config, "enforce_eager", False)
)
if not v1_eager:
logger.warning(
"KV-prune compression: v1 CUDA graphs are still enabled on this LLM. "
"The compactor does not reuse v1 graphs; capture wastes VRAM. "
"Set kvprune_compression=True, enforce_eager=True, or "
"VLLM_KVPRUNE_COMPRESSION_DEFAULT=1 before import vllm."
)
if pc.tensor_parallel_size > 1:
return _compressed_generate_tp_collective(llm, plist, sps, comps)
ensure_inprocess_engine_for_weight_sharing()
if llm._kvprune_compactor_engine is None:
_maybe_release_v1_kv_for_compactor(llm)
engine = _ensure_compactor_engine(llm)
comp_sp = [_to_compactor_sampling(sp) for sp in sps]
seq_c = [_to_sequence_compression(c) for c in comps]
batch_c = _batch_compression_from_comps(comps)
comp_in = [_prompt_to_compactor_input(p) for p in plist]
_, seqs = engine.generate(
comp_in,
sampling_params=comp_sp,
batch_compression_params=batch_c,
per_sequence_compression_params=seq_c,
return_sequences=True,
)
return _sequences_to_request_outputs(seqs, engine)
def _sequences_to_request_outputs(seqs: list[Any], engine: LLMEngine) -> list[RequestOutput]:
tok = engine.tokenizer
out: list[RequestOutput] = []
for i, seq in enumerate(seqs):
text = tok.decode(seq.completion_token_ids, skip_special_tokens=True)
# If every emitted id is “special” (e.g. EOS / chat boundary), the stripped
# string is empty while ``completion_token_ids`` is non-empty — avoid
# presenting a blank answer so users can see boundary tokens / debug.
if not text.strip() and seq.completion_token_ids:
text = tok.decode(seq.completion_token_ids, skip_special_tokens=False)
co = CompletionOutput(
index=0,
text=text,
token_ids=list(seq.completion_token_ids),
cumulative_logprob=None,
logprobs=None,
finish_reason="stop",
)
ro = RequestOutput(
request_id=f"kvprune-{i}",
prompt=None,
prompt_token_ids=list(seq.prompt_token_ids),
prompt_logprobs=None,
outputs=[co],
finished=True,
)
out.append(ro)
return out
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