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sglang/python/sglang/jit_kernel/tests/test_nvfp4_blockwise_moe.py
2026-03-07 10:31:08 +08:00

128 lines
4.4 KiB
Python

import pytest
import torch
from sglang.jit_kernel.nvfp4 import (
cutlass_fp4_group_mm,
scaled_fp4_experts_quant,
scaled_fp4_quant,
)
FLOAT4_E2M1_MAX = 6.0
FLOAT8_E4M3_MAX = torch.finfo(torch.float8_e4m3fn).max
def _nvfp4_supported() -> bool:
return torch.cuda.is_available() and torch.cuda.get_device_capability() >= (10, 0)
def _round_up(x: int, y: int) -> int:
return ((x + y - 1) // y) * y
def _build_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 _build_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)
@pytest.mark.skipif(
not _nvfp4_supported(), reason="NVFP4 requires compute capability >= 10.0"
)
@pytest.mark.parametrize("dtype", [torch.float16, torch.bfloat16])
def test_nvfp4_blockwise_moe_grouped_mm(dtype: torch.dtype) -> None:
torch.manual_seed(0)
device = torch.device("cuda")
num_experts = 4
m_per_expert = [33, 17, 48, 29]
n = 256
k = 128
expert_offsets_full = _build_expert_offsets(m_per_expert, device)
blockscale_offsets_full = _build_blockscale_offsets(m_per_expert, device)
total_m = int(expert_offsets_full[-1].item())
a = torch.randn((total_m, 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())
amax = a[start:end].abs().max().to(torch.float32)
a_global_scale[i] = FLOAT8_E4M3_MAX * FLOAT4_E2M1_MAX / amax
b_global_scale = torch.empty((num_experts,), device=device, dtype=torch.float32)
for i in range(num_experts):
bmax = b[i].abs().max().to(torch.float32)
b_global_scale[i] = FLOAT8_E4M3_MAX * FLOAT4_E2M1_MAX / bmax
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),
}
out = cutlass_fp4_group_mm(
a_fp4,
b_fp4,
a_blockscale,
b_blockscale,
alphas,
dtype,
params,
)
ref = torch.empty((total_m, n), device=device, dtype=dtype)
for i in range(num_experts):
start = int(expert_offsets_full[i].item())
end = int(expert_offsets_full[i + 1].item())
ref[start:end] = torch.matmul(a[start:end], b[i].t())
torch.testing.assert_close(out, ref, atol=1e-1, rtol=1e-1)