Files
enginex-bi_series-vllm/pkgs/xformers/benchmarks/benchmark_multi_head_dispatch.py
2025-08-05 19:02:46 +08:00

106 lines
3.3 KiB
Python

# Copyright (c) Facebook, Inc. and its affiliates. All rights reserved.
#
# This source code is licensed under the BSD license found in the
# LICENSE file in the root directory of this source tree.
from typing import Any, Dict
import torch
import torch.nn as nn
import triton
from xformers.benchmarks.utils import TestCase, pretty_plot, pretty_print
from xformers.components import MultiHeadDispatch
from xformers.components.attention import ScaledDotProduct
SHAPES = [
(8, 384, 128),
(8, 784, 512),
(4, 1024, 768),
(4, 2048, 1024),
(2, 2048, 2048),
(2, 2048, 4096),
(2, 4096, 4096),
(1, 2048, 12288),
]
N_HEADS = [4]
def bench_multihead_dispatch(backward: bool, self_attention: bool):
device = torch.device("cuda")
bw = "+bw" if backward else ""
sa = " (self_attn)" if self_attention else ""
for dtype in [torch.float16, torch.float32]:
results: Dict[str, Any] = {}
for B, M, K in SHAPES:
for heads in N_HEADS:
xf_multi_head = MultiHeadDispatch(
dim_model=K,
residual_dropout=0.0,
num_heads=heads,
attention=ScaledDotProduct(),
bias=(True, True, True, True),
).to(device=device, dtype=dtype)
torch_multi_head = nn.MultiheadAttention(
embed_dim=K, num_heads=heads, batch_first=True
).to(device=device, dtype=dtype)
q = torch.randn(
(B, M, K), requires_grad=backward, device=device, dtype=dtype
)
if self_attention:
k = q
v = q
else:
k = torch.randn(
(B, M, K), requires_grad=backward, device=device, dtype=dtype
)
v = torch.randn(
(B, M, K), requires_grad=backward, device=device, dtype=dtype
)
def torch_mha():
y, _ = torch_multi_head(query=q, key=k, value=v)
if backward:
torch.norm(y).backward()
return y
def xformers_mha():
y = xf_multi_head(query=q, key=k, value=v)
if backward:
torch.norm(y).backward()
return y
for testcase in [
TestCase(torch_mha, f"torch - fw{bw}{sa}"),
TestCase(xformers_mha, f"xf - fw{bw}{sa}"),
]:
time = triton.testing.do_bench(testcase.function)[0]
key = f"B={B}, M={M}, K={K}, N_HEADS={heads}"
if key not in results:
results[key] = {}
results[key][testcase.name] = f"{time:.2f}"
pretty_print(
results,
title=f"\n --- Type: {dtype} --- ",
units="runtime in ms, lower is better",
)
pretty_plot(
results,
title=f"MHA-FW{bw}-{dtype}",
units="runtime in ms, lower is better",
dash_key="torch",
)
for bw in [False, True]:
for self_attention in [False, True]:
bench_multihead_dispatch(bw, self_attention)