[NVIDIA] Add fp8 gemm benchmark on blackwell (#13528)

This commit is contained in:
Kaixi Hou
2025-11-19 19:35:00 -08:00
committed by GitHub
parent dc69462456
commit c3c4da71fb
2 changed files with 331 additions and 2 deletions

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@@ -0,0 +1,329 @@
import argparse
from typing import Tuple
import torch
import triton
from deep_gemm import ceil_div
from flashinfer.gemm import gemm_fp8_nt_groupwise
from sglang.srt.layers.quantization.fp8_kernel import (
sglang_per_token_group_quant_fp8,
w8a8_block_fp8_matmul_deepgemm,
)
from sglang.srt.layers.quantization.fp8_utils import requant_weight_ue8m0
BLOCK_SIZE = 128
def per_block_cast_to_fp8(x: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor]:
assert x.dim() == 2
assert BLOCK_SIZE == 128
m, n = x.shape
x_padded = torch.zeros(
(ceil_div(m, 128) * 128, ceil_div(n, 128) * 128), dtype=x.dtype, device=x.device
)
x_padded[:m, :n] = x
x_view = x_padded.view(-1, 128, x_padded.size(1) // 128, 128)
x_amax = x_view.abs().float().amax(dim=(1, 3), keepdim=True).clamp(1e-4)
x_scaled = (x_view * (448.0 / x_amax)).to(torch.float8_e4m3fn)
return x_scaled.view_as(x_padded)[:m, :n].contiguous(), (x_amax / 448.0).view(
x_view.size(0), x_view.size(2)
)
def get_weight_shapes(tp_size):
# cannot TP
total = [
(512 + 64, 7168),
((128 + 64) * 128, 7168),
(128 * (128 + 128), 512),
(7168, 16384),
(7168, 18432),
]
# N can TP
n_tp = [
(18432 * 2, 7168),
((128 + 64) * 128, 7168),
(128 * (128 + 128), 512),
(24576, 1536),
(4096, 7168),
]
# K can TP
k_tp = [(7168, 18432), (7168, 16384), (7168, 2048)]
weight_shapes = []
for t in total:
weight_shapes.append(t)
for n_t in n_tp:
new_t = (n_t[0] // tp_size, n_t[1])
weight_shapes.append(new_t)
for k_t in k_tp:
new_t = (k_t[0], k_t[1] // tp_size)
weight_shapes.append(new_t)
return weight_shapes
def create_benchmark_configs(tp_size):
configs = []
weight_shapes = get_weight_shapes(tp_size)
batch_sizes = [8, 16, 32, 64, 128, 256, 1024, 2048, 4096]
for n, k in weight_shapes:
for m in batch_sizes:
configs.append((m, n, k, tp_size))
return configs
def fp8_gemm_flashinfer(
x_fp8: torch.Tensor,
x_scale: torch.Tensor,
y_fp8: torch.Tensor,
y_scale: torch.Tensor,
):
"""Flashinfer implementation of FP8 GEMM"""
output = gemm_fp8_nt_groupwise(
x_fp8,
y_fp8,
x_scale,
y_scale,
out_dtype=torch.bfloat16,
backend="trtllm",
)
return output
def fp8_gemm_deepgemm_blackwell(
x_fp8: torch.Tensor,
x_scale: torch.Tensor,
y_fp8: torch.Tensor,
y_scale: torch.Tensor,
):
"""DeepGEMM implementation of FP8 GEMM"""
block_size = [BLOCK_SIZE, BLOCK_SIZE]
output = w8a8_block_fp8_matmul_deepgemm(
x_fp8, y_fp8, x_scale, y_scale, block_size, output_dtype=torch.bfloat16
)
return output
def check_accuracy(a, b, atol, rtol, percent):
"""Unified accuracy checking function with detailed error reporting."""
if not torch.isfinite(a).all():
print("Non-finite values in reference output")
return False
if not torch.isfinite(b).all():
print("Non-finite values in actual output")
return False
assert a.shape == b.shape, f"Shape mismatch: {a.shape} vs {b.shape}"
close = torch.isclose(a, b, atol=atol, rtol=rtol)
match_ratio = close.float().mean()
if match_ratio >= percent:
return True
mismatch_percent = 1.0 - match_ratio.item()
if mismatch_percent > 1 - percent:
print(
f"Mismatch percentage is {mismatch_percent:.4f} for rtol {rtol} "
f"(threshold: {1 - percent:.4f})"
)
return False
def calculate_diff(m: int, n: int, k: int):
x = torch.randn((m, k), device="cuda", dtype=torch.bfloat16)
y = torch.randn((n, k), device="cuda", dtype=torch.bfloat16)
y_fp8, y_scale = per_block_cast_to_fp8(y)
x_fp8, x_scale = sglang_per_token_group_quant_fp8(
x, BLOCK_SIZE, column_major_scales=True
)
out_flashinfer = fp8_gemm_flashinfer(
x_fp8,
x_scale,
y_fp8,
y_scale,
)
dg_x_fp8, dg_x_scale = sglang_per_token_group_quant_fp8(
x,
BLOCK_SIZE,
column_major_scales=True,
scale_tma_aligned=True,
scale_ue8m0=True,
)
# We can directly quantize y here, but to mimic the behavior of the actual
# implementations, we requant it here.
dg_y_fp8, dg_y_scale = requant_weight_ue8m0(
y_fp8, y_scale, [BLOCK_SIZE, BLOCK_SIZE]
)
out_deepgemm = fp8_gemm_deepgemm_blackwell(
dg_x_fp8, dg_x_scale, dg_y_fp8, dg_y_scale
)
print(f"Shape m={m}, n={n}, k={k}:")
print(f"Flashinfer output: {out_flashinfer[0, 0:5]}")
print(f"DeepGEMM output: {out_deepgemm[0, 0:5]}")
flashinfer_deepgemm_match = check_accuracy(
out_flashinfer, out_deepgemm, 0.1, 0.6, 0.95
)
print("Correctness check:")
print(f" - Flashinfer vs DeepGEMM: {'' if flashinfer_deepgemm_match else ''}")
def _benchmark(m, n, k, tp_size, provider):
print(f"Shape (m={m}, n={n}, k={k}, tp={tp_size}), Provider: {provider}")
x = torch.randn((m, k), device="cuda", dtype=torch.bfloat16)
y = torch.randn((n, k), device="cuda", dtype=torch.bfloat16)
# Preprocess data before benchmarking
y_fp8, y_scale = per_block_cast_to_fp8(y)
x_fp8, x_scale = sglang_per_token_group_quant_fp8(
x, BLOCK_SIZE, column_major_scales=True
)
dg_x_fp8, dg_x_scale = sglang_per_token_group_quant_fp8(
x,
BLOCK_SIZE,
column_major_scales=True,
scale_tma_aligned=True,
scale_ue8m0=True,
)
dg_y_fp8, dg_y_scale = requant_weight_ue8m0(
y_fp8, y_scale, [BLOCK_SIZE, BLOCK_SIZE]
)
quantiles = [0.5, 0.2, 0.8]
if provider == "deepgemm":
ms, min_ms, max_ms = triton.testing.do_bench(
lambda: fp8_gemm_deepgemm_blackwell(
dg_x_fp8,
dg_x_scale,
dg_y_fp8,
dg_y_scale,
),
quantiles=quantiles,
)
elif provider == "flashinfer":
ms, min_ms, max_ms = triton.testing.do_bench(
lambda: fp8_gemm_flashinfer(
x_fp8,
x_scale,
y_fp8,
y_scale,
),
quantiles=quantiles,
)
# Calculate TFLOPS
flops = 2 * m * n * k # multiply-adds
tflops = flops / (ms * 1e-3) / 1e12
# Print shape-specific results with TFLOPS
print(f"Time: {ms*1000:.2f} us, TFLOPS: {tflops:.2f}")
return ms, max_ms, min_ms
def get_benchmark_plot_friendly(tp_size):
all_configs = create_benchmark_configs(tp_size)
x_vals = list(range(len(all_configs)))
@triton.testing.perf_report(
triton.testing.Benchmark(
x_names=["cfg_id"],
x_vals=x_vals,
line_arg="provider",
line_vals=["deepgemm", "flashinfer"],
line_names=["DeepGEMM", "Flashinfer"],
styles=[("blue", "-"), ("red", "-")],
ylabel="us",
plot_name=f"fp8-gemm-performance-comparison-tp{tp_size}",
args={},
)
)
def benchmark(cfg_id, provider):
m, n, k, tp_size = all_configs[cfg_id]
ms, min_ms, max_ms = _benchmark(m, n, k, tp_size, provider)
return ms * 1000, max_ms * 1000, min_ms * 1000 # convert to ms
return benchmark
def get_benchmark(tp_size):
all_configs = create_benchmark_configs(tp_size)
@triton.testing.perf_report(
triton.testing.Benchmark(
x_names=["m", "n", "k", "tp_size"],
x_vals=[list(config) for config in all_configs],
line_arg="provider",
line_vals=["deepgemm", "flashinfer"],
line_names=["DeepGEMM", "Flashinfer"],
styles=[("blue", "-"), ("red", "-")],
ylabel="us",
plot_name=f"fp8-gemm-performance-comparison-tp{tp_size}",
args={},
)
)
def benchmark(m, n, k, tp_size, provider):
ms, min_ms, max_ms = _benchmark(m, n, k, tp_size, provider)
return ms * 1000, max_ms * 1000, min_ms * 1000 # convert to ms
return benchmark
if __name__ == "__main__":
if not torch.cuda.is_available() or torch.cuda.get_device_capability()[0] != 10:
print("Skipping benchmark because the device is not supported")
exit(0)
parser = argparse.ArgumentParser()
parser.add_argument(
"--save-path",
type=str,
default="./configs/benchmark_ops/fp8_gemm/",
help="Path to save fp8 gemm benchmark results",
)
parser.add_argument(
"--run-correctness",
action="store_true",
default=True,
help="Whether to run correctness test",
)
parser.add_argument(
"--tp-size",
type=int,
default=1,
help="Tensor parallelism size to benchmark (default: 1)",
)
parser.add_argument(
"--plot-friendly",
action="store_true",
default=False,
help="Plot x axis as the config index instead of the m",
)
args = parser.parse_args()
# Set random seed for reproducibility
torch.manual_seed(0)
torch.cuda.manual_seed(0)
# Run correctness tests on a few examples
if args.run_correctness:
print("Running correctness tests...")
calculate_diff(64, 512, 7168) # Small test
calculate_diff(64, 7168, 16384) # Medium test
calculate_diff(64, 18432, 7168) # Large test
# Get the benchmark function with the specified tp_size
benchmark = (
get_benchmark_plot_friendly(args.tp_size)
if args.plot_friendly
else get_benchmark(args.tp_size)
)
print(f"Running performance benchmark for TP size = {args.tp_size}...")
benchmark.run(print_data=True, save_path=args.save_path)

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@@ -439,7 +439,7 @@ def requant_weight_ue8m0_inplace(weight, weight_scale_inv, weight_block_size):
assert isinstance(weight, torch.nn.Parameter)
assert isinstance(weight_scale_inv, torch.nn.Parameter)
new_weight, new_weight_scale_inv = _requant_weight_ue8m0(
new_weight, new_weight_scale_inv = requant_weight_ue8m0(
weight.to(weight_scale_inv.device), weight_scale_inv, weight_block_size
)
@@ -447,7 +447,7 @@ def requant_weight_ue8m0_inplace(weight, weight_scale_inv, weight_block_size):
weight_scale_inv.data = new_weight_scale_inv
def _requant_weight_ue8m0(
def requant_weight_ue8m0(
weight: torch.Tensor,
weight_scale_inv: torch.Tensor,
weight_block_size: List[int],