test_flash_mla_qkvfp8.py

import argparse
import math
import random

import torch
import triton

from flash_mla import flash_mla_with_kvcache_fp8, get_mla_decoding_metadata_dense_fp8
torch.set_printoptions(precision=4, profile="default", sci_mode=False)

def scaled_dot_product_attention(query, key, value, h_q, h_kv, is_causal=False, k_scale=1.0):
    query = query.float()
    key = key.float() * k_scale
    value = value.float() * k_scale
    key = key.repeat_interleave(h_q // h_kv, dim=0)
    value = value.repeat_interleave(h_q // h_kv, dim=0)
    tmp =  query @ key.transpose(-2, -1)
    # print("tmp s ", tmp[0, :4, :10])
    attn_weight = query @ key.transpose(-2, -1) / math.sqrt(query.size(-1))
    if is_causal:
        s_q = query.shape[-2]
        s_k = key.shape[-2]
        attn_bias = torch.zeros(s_q, s_k, dtype=query.dtype)
        temp_mask = torch.ones(s_q, s_k, dtype=torch.bool).tril(diagonal=s_k - s_q)
        attn_bias.masked_fill_(temp_mask.logical_not(), float("-inf"))
        attn_bias.to(query.dtype)
        attn_weight += attn_bias
    lse = attn_weight.logsumexp(dim=-1)
    attn_weight = torch.softmax(attn_weight, dim=-1, dtype=torch.float32)
    return attn_weight @ value, lse


def cal_diff(x: torch.Tensor, y: torch.Tensor, name: str, use_fp8: bool=False) -> None:
    torch_dtype = x.dtype
    x, y = x.double(), y.double()
    RMSE = ((x - y) * (x - y)).mean().sqrt().item()
    cos_diff = 1 - 2 * (x * y).sum().item() / max((x * x + y * y).sum().item(), 1e-12)
    amax_diff = (x - y).abs().max().item()
    print(f"{name}: {cos_diff=}, {RMSE=}, {amax_diff=}")
    if use_fp8:
        assert cos_diff < 1e-3
    else:
        assert cos_diff < (1e-4 if torch_dtype == torch.bfloat16 else 1e-5)

    


@torch.inference_mode()
def test_flash_mla(b, s_q, mean_sk, h_q, h_kv, d, dv, causal, varlen, is_prof=False,torch_dtype=torch.float16):
    print(
        f"{b=}, {s_q=}, {mean_sk=}, {h_q=}, {h_kv=}, {d=}, {dv=}, {causal=}, {varlen=}, {torch_dtype=}"
    )

    use_fp8 = torch_dtype == torch.float8_e4m3fn

    cache_seqlens = torch.full((b,), mean_sk, dtype=torch.int32)
    if varlen:
        for i in range(b):
            cache_seqlens[i] = max(random.normalvariate(mean_sk, mean_sk / 2), s_q)
    total_seqlens = cache_seqlens.sum().item()
    mean_seqlens = cache_seqlens.float().mean().int().item()
    max_seqlen = cache_seqlens.max().item()
    max_seqlen_pad = triton.cdiv(max_seqlen, 256) * 256
    print(f"{total_seqlens=}, {mean_seqlens=}, {max_seqlen=}, {max_seqlen_pad=}")

    q = torch.ones(b, s_q, h_q, d)
    q = torch.randn(b, s_q, h_q, d)
    # for i in range(576):
    #     q[:, :, :, i] = i
    # q[:, :, 1:, :] = 0
    # q = torch.ones(b, s_q, h_q, d)
    # print("q ", q[0, 0, 0:3, :10])
    block_size = 64
    block_table = torch.arange(
        b * max_seqlen_pad // block_size, dtype=torch.int32
    ).view(b, max_seqlen_pad // block_size)
    blocked_k = torch.ones(block_table.numel(), block_size, h_kv, d)
    blocked_k = torch.randn(block_table.numel(), block_size, h_kv, d)
    # blocked_k[:, :, :, 32:] = 0.0
    # blocked_k[:, 32:, :, :] = 0
    # blocked_k[:, :, :, 4:] = 0
    # blocked_k[:, :32, :, :] = 0
    # blocked_k[:, 16:, :, :] = 0
    for i in range(b):
        blocked_k.view(b, max_seqlen_pad, h_kv, d)[i, cache_seqlens[i].item():] = (
            float("nan")
        )
    blocked_v = blocked_k[..., :dv]

    tile_scheduler_metadata, num_splits = get_mla_decoding_metadata_dense_fp8(
        cache_seqlens, s_q * h_q // h_kv, h_kv
    )

    init_dtype = q.dtype
    def prepare_fp8_input():
        q_fp8, blocked_k_fp8, blocked_v_fp8, descale_q, descale_k = None, None, None, None, None

        if use_fp8:
            nonlocal q, blocked_k, blocked_v
            fp8_dtype = torch.float8_e4m3fn
            descale_q = torch.ones((1), dtype=torch.float32)
            descale_k = torch.ones((1), dtype=torch.float32)

            q_fp8 = q.to(fp8_dtype)
            blocked_k_fp8 = blocked_k.to(fp8_dtype)
            blocked_v_fp8 = blocked_k_fp8[..., :dv]

        return q_fp8, blocked_k_fp8, blocked_v_fp8, descale_q, descale_k

    q_fp8, blocked_k_fp8, blocked_v_fp8, descale_q, descale_k = prepare_fp8_input()
    
    # print(blocked_v_fp8[0, 32:36, 0, :4])
    if use_fp8:
        q = q_fp8
        blocked_k = blocked_k_fp8
        blocked_v = blocked_v_fp8
    # print(" descale_q  ", descale_q.shape, descale_q.stride())
    # print(" blocked_k ", blocked_k.shape)
    def flash_mla():
        return flash_mla_with_kvcache_fp8(
            q,
            blocked_k,
            block_table,
            cache_seqlens,
            dv,
            tile_scheduler_metadata,
            num_splits,
            causal=causal,
            descale_q=descale_q,
            descale_k=descale_k,
        )

    def ref_mla():
        q_ = (q.to(torch.float) * descale_q).to(init_dtype) if use_fp8 else q
        blocked_k_ = (blocked_k.to(torch.float) * descale_k).to(init_dtype) if use_fp8 else blocked_k
        blocked_v_ = (blocked_v.to(torch.float) * descale_k).to(init_dtype) if use_fp8 else blocked_v
        out = torch.empty(b, s_q, h_q, dv, dtype=torch.float32)
        lse = torch.empty(b, h_q, s_q, dtype=torch.float32)
        for i in range(b):
            begin = i * max_seqlen_pad
            end = begin + cache_seqlens[i]
            O, LSE = scaled_dot_product_attention(
                q_[i].transpose(0, 1),
                blocked_k_.view(-1, h_kv, d)[begin:end].transpose(0, 1),
                blocked_v_.view(-1, h_kv, dv)[begin:end].transpose(0, 1),
                h_q=h_q,
                h_kv=h_kv,
                is_causal=causal,
            )
            out[i] = O.transpose(0, 1)
            lse[i] = LSE
        return out, lse

    out_flash, lse_flash = flash_mla()
    
    out_torch, lse_torch = ref_mla()
    # print(" ", out_flash.shape, lse_flash.shape, q.shape)
    # print("out max_diff ", (out_flash - out_torch).abs().max())
    # print("lse max_diff ", (lse_flash - lse_torch).abs().max())

    # print(" diff ", torch.nonzero((lse_flash - lse_torch).abs() > 0.1))
    # print(" diff ", torch.nonzero((out_flash - out_torch).abs() > 0.1))
    # print(" out_torch ", out_torch[0, 0, 0, 0:10])
    # print(" out_flash ", out_flash[0, 0, 0,  0:10])
    # print(" lse_flash ", lse_flash[0,  0:3, :1])
    # print(" lse_torch ", lse_torch[0,  0:3, :1])
    # print(" nan ", torch.nonzero(torch.isnan(out_flash)))
    cal_diff(out_flash, out_torch, "out", use_fp8)
    cal_diff(lse_flash, lse_torch, "lse")
    if is_prof: return
    t = triton.testing.do_bench(flash_mla)
    FLOPS = s_q * total_seqlens * h_q * (d + dv) * 2
    bytes = (total_seqlens * h_kv * d + b * s_q * h_q * d) * (torch.finfo(torch_dtype).bits // 8) + (b * s_q * h_q * dv) * (torch.finfo(init_dtype).bits // 8)
    print(
        f"{t:.3f} ms, {FLOPS / 10 ** 9 / t:.0f} TFLOPS, {bytes / 10 ** 6 / t:.0f} GB/s"
    )

def get_gcn_arch_name() -> str:
    GPU_ARCH = torch.cuda.get_device_properties("cuda").gcnArchName
    return GPU_ARCH.split(':')[0]

def main(torch_dtype, is_prof=False):
    if get_gcn_arch_name() != "gfx938":
        print("[WARNING] The architecture is not supported.")
        exit(0) 
    device = torch.device("cuda:0")
    init_dtype = torch.bfloat16 if torch_dtype == torch.float8_e4m3fn else torch_dtype
    torch.set_default_dtype(init_dtype)
    torch.set_default_device(device)
    torch.cuda.set_device(device)
    torch.manual_seed(0)
    random.seed(0)
    '''
    h_kv = 1
    d, dv = 576, 512
    causal = True

    for b in [128]:
        for s in [4096, 8192]:
            for h_q in [16, 32, 64, 128]:  # TP = 8, 4, 2, 1
                for s_q in [1, 2]:  # MTP = 1, 2
                    for varlen in [False, True]:
                        test_flash_mla(b, s_q, s, h_q, h_kv, d, dv, causal, varlen)
    #                b, s_q,    s,   h_q, h_kv,   d,  dv, causal, varlen'''
    # test_flash_mla(  1,   1,  64,    16,    1, 576, 512,   True,  False, is_prof=is_prof)
    # test_flash_mla_fp8( 1,   1, 1000,     1,    1, 576, 512,   True,  False, is_prof=is_prof)
    # test_flash_mla_fp8( 1,   1, 4096,     8,    1, 576, 512,   True,  False, is_prof=is_prof)
    # test_flash_mla_fp8(32,   1, 4096,     16,    1, 576, 512,   False,  False, is_prof=is_prof)
    # '''
    h_kv = 1
    d, dv = 576, 512
    causal = True
   

    # for b in [40, 80]:
    #     for s in [3500, 4000, 8192, 16384]:
    #         for h_q in [16]:
    #             for s_q in [1]:  # MTP = 1, 2
    #                 for varlen in [False]:
    #                     test_flash_mla(b, s_q, s, h_q, h_kv, d, dv, causal, varlen,False,torch_dtype)
    # 压测
    for b in [3, 6, 9, 12, 15, 18, 21, 24, 40, 41, 79, 80]:
        for s in [111, 112, 123, 1234, 432, 4325, 4000, 8192, 12345, 45321]:
            for h_q in [32, 16, 64, 128]:
                for s_q in [1, 2, 3]:  # MTP = 1, 2
                    for varlen in [False, True]:
                        test_flash_mla(b, s_q, s, h_q, h_kv, d, dv, causal, varlen,True,torch_dtype)

    for b in [3, 6, 9, 12, 15, 18, 21, 24, 32, 64, 128, 256]:
        for s in [4000]:
            for h_q in [32, 16, 64, 128]:
                for s_q in [1]:  # MTP = 1, 2
                    for varlen in [False]:
                        test_flash_mla(b, s_q, s, h_q, h_kv, d, dv, causal, varlen,False,torch_dtype)

    for b in [3, 6, 9, 12, 15, 18, 21, 24, 32, 64, 128, 256]:
        for s in [4000]:
            for h_q in [16]:
                for s_q in [1,2,3,4]:  # MTP = 1, 2
                    for varlen in [False]:
                        test_flash_mla(b, s_q, s, h_q, h_kv, d, dv, causal, varlen,False,torch_dtype)



    # '''

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--dtype",
        type=str,
        choices=["bf16", "fp16","e4m3"],
        default="bf16",
        help="Data type to use for testing (bf16/fp16/e4m3)",
    )
    parser.add_argument('--prof', default=False, action='store_true', help='prof or not')

    args = parser.parse_args()

    torch_dtype = torch.float8_e4m3fn
    if args.dtype == "fp16":
        torch_dtype = torch.float16
    elif args.dtype == "e4m3":
        torch_dtype = torch.float8_e4m3fn
    main(torch_dtype, args.prof)