Files
vllm/benchmarks/kernels/bench_block_fp8_gemm.py
2025-08-29 10:28:35 -07:00

115 lines
3.5 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import torch
from vllm.model_executor.layers.quantization.utils.fp8_utils import (
w8a8_block_fp8_matmul,
)
from vllm.platforms import current_platform
from vllm.triton_utils import triton as vllm_triton
assert current_platform.is_cuda(), (
"Only support benchmarking w8a8 block fp8 kernel on CUDA device."
)
# DeepSeek-V3 weight shapes
DEEPSEEK_V3_SHAPES = [
(512 + 64, 7168),
(2112, 7168),
((128 + 64) * 128, 7168),
(128 * (128 + 128), 512),
(7168, 16384),
(7168, 18432),
(18432 * 2, 7168),
(24576, 1536),
(12288, 7168),
(4096, 7168),
(7168, 2048),
]
def build_w8a8_block_fp8_runner(M, N, K, block_size, device):
"""Build runner function for w8a8 block fp8 matmul."""
factor_for_scale = 1e-2
fp8_info = torch.finfo(torch.float8_e4m3fn)
fp8_max, fp8_min = fp8_info.max, fp8_info.min
# Create random FP8 tensors
A_fp32 = (torch.rand(M, K, dtype=torch.float32, device=device) - 0.5) * 2 * fp8_max
A = A_fp32.clamp(min=fp8_min, max=fp8_max).to(torch.float8_e4m3fn)
B_fp32 = (torch.rand(N, K, dtype=torch.float32, device=device) - 0.5) * 2 * fp8_max
B = B_fp32.clamp(min=fp8_min, max=fp8_max).to(torch.float8_e4m3fn)
# Create scales
block_n, block_k = block_size[0], block_size[1]
n_tiles = (N + block_n - 1) // block_n
k_tiles = (K + block_k - 1) // block_k
As = torch.rand(M, k_tiles, dtype=torch.float32, device=device) * factor_for_scale
Bs = (
torch.rand(n_tiles, k_tiles, dtype=torch.float32, device=device)
* factor_for_scale
)
def run():
return w8a8_block_fp8_matmul(A, B, As, Bs, block_size, torch.bfloat16)
return run
@vllm_triton.testing.perf_report(
vllm_triton.testing.Benchmark(
x_names=["batch_size"],
x_vals=[1, 16, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384],
x_log=False,
line_arg="provider",
line_vals=["torch-bf16", "w8a8-block-fp8"],
line_names=["torch-bf16", "w8a8-block-fp8"],
ylabel="TFLOP/s (larger is better)",
plot_name="BF16 vs W8A8 Block FP8 GEMMs",
args={},
)
)
def benchmark_tflops(batch_size, provider, N, K, block_size=(128, 128)):
M = batch_size
device = "cuda"
quantiles = [0.5, 0.2, 0.8]
if provider == "torch-bf16":
a = torch.randn((M, K), device=device, dtype=torch.bfloat16)
b = torch.randn((N, K), device=device, dtype=torch.bfloat16)
ms, min_ms, max_ms = vllm_triton.testing.do_bench_cudagraph(
lambda: torch.nn.functional.linear(a, b), quantiles=quantiles
)
else: # w8a8-block-fp8
run_w8a8 = build_w8a8_block_fp8_runner(M, N, K, block_size, device)
ms, min_ms, max_ms = vllm_triton.testing.do_bench_cudagraph(
lambda: run_w8a8(), quantiles=quantiles
)
to_tflops = lambda t_ms: (2 * M * N * K) * 1e-12 / (t_ms * 1e-3)
return to_tflops(ms), to_tflops(max_ms), to_tflops(min_ms)
if __name__ == "__main__":
block_size = (128, 128)
for N, K in DEEPSEEK_V3_SHAPES:
print(f"\nBenchmarking DeepSeek-V3, N={N} K={K}")
print(f"TFLOP/s comparison (block_size={block_size}):")
benchmark_tflops.run(
print_data=True,
# show_plots=False,
# save_path=f"bench_w8a8_block_fp8_tflops_n{N}_k{K}",
N=N,
K=K,
block_size=block_size,
)
print("\nBenchmark finished!")