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sglang/python/sglang/jit_kernel/benchmark/bench_nvfp4_blockwise_moe.py

259 lines
8.5 KiB
Python

from __future__ import annotations
import sys
from typing import Any
import torch
import triton
from sglang.jit_kernel.benchmark.utils import get_benchmark_range, run_benchmark
from sglang.jit_kernel.nvfp4 import (
cutlass_fp4_group_mm,
scaled_fp4_experts_quant,
scaled_fp4_quant,
)
from sglang.srt.utils import is_sm100_supported
FLOAT4_E2M1_MAX = 6.0
FLOAT8_E4M3_MAX = torch.finfo(torch.float8_e4m3fn).max
_NVFP4_SUPPORTED = is_sm100_supported()
def _round_up(x: int, y: int) -> int:
return ((x + y - 1) // y) * y
def _expert_offsets(m_per_expert: list[int], device: torch.device) -> torch.Tensor:
offsets = [0]
for m in m_per_expert:
offsets.append(offsets[-1] + m)
return torch.tensor(offsets, dtype=torch.int32, device=device)
def _blockscale_offsets(m_per_expert: list[int], device: torch.device) -> torch.Tensor:
offsets = [0]
for m in m_per_expert:
offsets.append(offsets[-1] + _round_up(m, 128))
return torch.tensor(offsets, dtype=torch.int32, device=device)
def _prepare_case(
total_tokens: int, n: int, k: int, num_experts: int, dtype: torch.dtype
) -> dict[str, Any]:
device = torch.device("cuda")
base = total_tokens // num_experts
rem = total_tokens % num_experts
m_per_expert = [base + (1 if i < rem else 0) for i in range(num_experts)]
expert_offsets_full = _expert_offsets(m_per_expert, device)
blockscale_offsets_full = _blockscale_offsets(m_per_expert, device)
a = torch.randn((total_tokens, k), device=device, dtype=dtype) * 0.1
b = torch.randn((num_experts, n, k), device=device, dtype=dtype) * 0.1
a_global_scale = torch.empty((num_experts,), device=device, dtype=torch.float32)
for i in range(num_experts):
start = int(expert_offsets_full[i].item())
end = int(expert_offsets_full[i + 1].item())
a_global_scale[i] = (
FLOAT8_E4M3_MAX
* FLOAT4_E2M1_MAX
/ a[start:end].abs().max().to(torch.float32)
)
b_global_scale = torch.empty((num_experts,), device=device, dtype=torch.float32)
for i in range(num_experts):
b_global_scale[i] = (
FLOAT8_E4M3_MAX * FLOAT4_E2M1_MAX / b[i].abs().max().to(torch.float32)
)
a_fp4, a_blockscale = scaled_fp4_experts_quant(
a,
a_global_scale,
expert_offsets_full,
blockscale_offsets_full,
topk=1,
)
b_fp4 = torch.empty((num_experts, n, k // 2), device=device, dtype=torch.uint8)
b_blockscale = torch.empty(
(num_experts, _round_up(n, 128), _round_up(k // 16, 4)),
device=device,
dtype=torch.float8_e4m3fn,
)
for i in range(num_experts):
b_fp4_i, b_scale_i = scaled_fp4_quant(b[i], b_global_scale[i])
b_fp4[i].copy_(b_fp4_i)
b_blockscale[i].copy_(b_scale_i)
alphas = (1.0 / (a_global_scale * b_global_scale)).to(torch.float32)
params = {
"ab_strides": torch.full((num_experts,), k, dtype=torch.int64, device=device),
"c_strides": torch.full((num_experts,), n, dtype=torch.int64, device=device),
"problem_sizes": torch.tensor(
[[m, n, k] for m in m_per_expert], dtype=torch.int32, device=device
),
"expert_offsets": expert_offsets_full[:-1].contiguous(),
"blockscale_offsets": blockscale_offsets_full[:-1].contiguous(),
"a_ptrs": torch.empty((num_experts,), dtype=torch.int64, device=device),
"b_ptrs": torch.empty((num_experts,), dtype=torch.int64, device=device),
"out_ptrs": torch.empty((num_experts,), dtype=torch.int64, device=device),
"a_scales_ptrs": torch.empty((num_experts,), dtype=torch.int64, device=device),
"b_scales_ptrs": torch.empty((num_experts,), dtype=torch.int64, device=device),
"alpha_ptrs": torch.empty((num_experts,), dtype=torch.int64, device=device),
"layout_sfa": torch.empty((num_experts, 5), dtype=torch.int64, device=device),
"layout_sfb": torch.empty((num_experts, 5), dtype=torch.int64, device=device),
}
expert_ranges: list[tuple[int, int]] = []
start = 0
for m in m_per_expert:
end = start + m
expert_ranges.append((start, end))
start = end
return {
"a": a,
"b": b,
"a_fp4": a_fp4,
"b_fp4": b_fp4,
"a_blockscale": a_blockscale,
"b_blockscale": b_blockscale,
"alphas": alphas,
"params": params,
"expert_offsets_full": expert_offsets_full,
"expert_ranges": expert_ranges,
"dtype": dtype,
}
def _torch_ref_group_mm(case: dict[str, Any]) -> torch.Tensor:
a = case["a"]
b = case["b"]
dtype = case["dtype"]
expert_ranges = case["expert_ranges"]
total_tokens = a.shape[0]
n = b.shape[1]
out = torch.empty((total_tokens, n), device=a.device, dtype=dtype)
for i, (start, end) in enumerate(expert_ranges):
out[start:end] = torch.matmul(a[start:end], b[i].t())
return out
def _aot_cutlass_fp4_group_mm(case: dict[str, Any]) -> torch.Tensor:
a_fp4 = case["a_fp4"]
b_fp4 = case["b_fp4"]
a_blockscale = case["a_blockscale"]
b_blockscale = case["b_blockscale"]
alphas = case["alphas"]
params = case["params"]
out_dtype = case["dtype"]
out = torch.empty(
(a_fp4.shape[0], b_fp4.shape[1]), device=a_fp4.device, dtype=out_dtype
)
torch.ops.sgl_kernel.cutlass_fp4_group_mm.default(
out,
a_fp4,
b_fp4,
a_blockscale,
b_blockscale,
alphas,
params["ab_strides"],
params["c_strides"],
params["problem_sizes"],
params["expert_offsets"],
params["blockscale_offsets"],
)
return out
def _probe_legacy_aot_group_mm() -> tuple[bool, str]:
if not torch.cuda.is_available():
return False, "CUDA is not available."
if not _NVFP4_SUPPORTED:
return False, "NVFP4 benchmarks require sm100+ with CUDA 12.8+."
try:
import sgl_kernel # noqa: F401
except Exception as e:
return False, f"import sgl_kernel failed: {e}"
if not hasattr(torch.ops, "sgl_kernel"):
return False, "torch.ops.sgl_kernel is not registered."
op = getattr(torch.ops.sgl_kernel, "cutlass_fp4_group_mm", None)
if op is None or not hasattr(op, "default"):
return False, "torch.ops.sgl_kernel.cutlass_fp4_group_mm.default is missing."
try:
case = _prepare_case(64, 256, 128, 4, torch.bfloat16)
_aot_cutlass_fp4_group_mm(case)
torch.cuda.synchronize()
except Exception as e:
return False, f"calling AOT grouped_mm op failed: {e}"
return True, ""
_AOT_GROUP_MM_AVAILABLE, _AOT_GROUP_MM_REASON = _probe_legacy_aot_group_mm()
shape_range = get_benchmark_range(
full_range=[(128, 256, 128, 4), (256, 512, 128, 8), (512, 512, 256, 8)],
ci_range=[(128, 256, 128, 4)],
)
line_vals = ["jit"]
line_names = ["JIT NVFP4 MoE GroupMM"]
styles = [("green", "-")]
if _AOT_GROUP_MM_AVAILABLE:
line_vals.append("aot_sgl_kernel")
line_names.append("AOT NVFP4 MoE GroupMM")
styles.append(("orange", "-"))
line_vals.append("torch_ref")
line_names.append("Torch Ref")
styles.append(("blue", "-"))
@triton.testing.perf_report(
triton.testing.Benchmark(
x_names=["total_tokens", "n", "k", "num_experts"],
x_vals=shape_range,
x_log=False,
line_arg="provider",
line_vals=line_vals,
line_names=line_names,
styles=styles,
ylabel="us",
plot_name="nvfp4-blockwise-moe-groupmm-performance",
args={},
)
)
def benchmark(total_tokens, n, k, num_experts, provider):
case = _prepare_case(total_tokens, n, k, num_experts, torch.bfloat16)
if provider == "jit":
fn = lambda: cutlass_fp4_group_mm(
case["a_fp4"],
case["b_fp4"],
case["a_blockscale"],
case["b_blockscale"],
case["alphas"],
case["dtype"],
case["params"],
)
elif provider == "aot_sgl_kernel":
fn = lambda: _aot_cutlass_fp4_group_mm(case)
elif provider == "torch_ref":
fn = lambda: _torch_ref_group_mm(case)
else:
raise ValueError(f"Unknown provider: {provider}")
return run_benchmark(fn)
if __name__ == "__main__":
if not _NVFP4_SUPPORTED:
print("[skip] NVFP4 blockwise MoE benchmark requires sm100+ with CUDA 12.8+.")
sys.exit(0)
if not _AOT_GROUP_MM_AVAILABLE:
print(
f"[info] legacy AOT grouped_mm baseline unavailable: {_AOT_GROUP_MM_REASON}"
)
benchmark.run(print_data=True)