Files
vllm/benchmarks/kernels/benchmark_per_token_group_quant.py
2025-07-30 07:15:02 -07:00

160 lines
4.6 KiB
Python
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import argparse
import math
from contextlib import contextmanager
from typing import Callable
from unittest.mock import patch
import torch
from vllm.model_executor.layers.quantization.utils import fp8_utils, int8_utils
from vllm.platforms import current_platform
@contextmanager
def _triton_mode():
"""Temporarily force the Triton fallback path"""
with patch("vllm.platforms.current_platform.is_cuda", return_value=False):
yield
def _time_cuda(
fn: Callable[[], tuple[torch.Tensor, torch.Tensor]],
warmup_iters: int,
bench_iters: int,
) -> float:
# warmup
for _ in range(warmup_iters):
fn()
torch.cuda.synchronize()
start = torch.cuda.Event(enable_timing=True)
end = torch.cuda.Event(enable_timing=True)
start.record()
for _ in range(bench_iters):
fn()
end.record()
torch.cuda.synchronize()
return start.elapsed_time(end) / bench_iters # ms/iter
def _run_single(
shape: tuple[int, int],
group_size: int,
dtype: str,
*,
column_major: bool = False,
scale_ue8m0: bool = False,
warmup_iters: int,
bench_iters: int,
) -> None:
num_tokens, hidden_dim = shape
device = torch.device("cuda")
torch.manual_seed(42)
x = torch.randn(num_tokens, hidden_dim, device=device, dtype=torch.bfloat16) * 8
if dtype == "fp8":
def cuda_impl():
return fp8_utils.per_token_group_quant_fp8(
x,
group_size,
column_major_scales=column_major,
use_ue8m0=scale_ue8m0,
)
def triton_impl():
with _triton_mode():
return fp8_utils.per_token_group_quant_fp8(
x,
group_size,
column_major_scales=column_major,
use_ue8m0=scale_ue8m0,
)
elif dtype == "int8":
def cuda_impl():
return int8_utils.per_token_group_quant_int8(x, group_size)
def triton_impl():
with _triton_mode():
return int8_utils.per_token_group_quant_int8(x, group_size)
else:
raise ValueError("dtype must be 'fp8' or 'int8'")
cuda_ms = _time_cuda(cuda_impl, warmup_iters, bench_iters)
triton_ms = _time_cuda(triton_impl, warmup_iters, bench_iters)
speedup = triton_ms / cuda_ms if cuda_ms else math.inf
cfg_desc = (
f"shape={shape} gs={group_size:<3} col_major={column_major:<5} "
f"ue8m0={scale_ue8m0:<5} dtype={dtype}"
)
print(
f"{cfg_desc:55} | CUDA {cuda_ms:7.3f} ms | Triton {triton_ms:7.3f} ms | "
f"speed-up ×{speedup:5.2f}"
)
def parse_args():
parser = argparse.ArgumentParser()
parser.add_argument("--warmup-iters", type=int, default=10)
parser.add_argument("--bench-iters", type=int, default=100)
parser.add_argument("--dtype", choices=["fp8", "int8", "both"], default="both")
return parser.parse_args()
if __name__ == "__main__":
if not current_platform.is_cuda():
raise RuntimeError("CUDA device is required to run this benchmark.")
args = parse_args()
warmup_iters, bench_iters = args.warmup_iters, args.bench_iters
shapes = [(32, 128), (64, 256), (16, 512)]
group_sizes = [64, 128]
dtypes = ["fp8", "int8"] if args.dtype == "both" else [args.dtype]
header = (
"Configuration".ljust(55)
+ " | "
+ "CUDA (ms)".center(12)
+ " | "
+ "Triton (ms)".center(13)
+ " | "
+ "Speed-up"
)
print(header)
print("-" * len(header))
for dtype in dtypes:
for shape in shapes:
for gs in group_sizes:
if dtype == "fp8":
for col_major in (False, True):
for ue8m0 in (False, True):
_run_single(
shape,
gs,
dtype,
column_major=col_major,
scale_ue8m0=ue8m0,
warmup_iters=warmup_iters,
bench_iters=bench_iters,
)
else: # INT8 has no col-major / ue8m0 switches
_run_single(
shape,
gs,
dtype,
warmup_iters=warmup_iters,
bench_iters=bench_iters,
)