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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""Tests for fp32_router_gemm kernel: activation×weight→fp32.
Supported (hidden_size, num_experts) pairs:
(3072, 256) -> MiniMax-M2/M2.5, (6144, 128) -> MiniMax-M3,
(6144, 256) -> GLM-5.2
Correctness baseline: F.linear in float32. Every M in [1, 32] is covered so
all tuned geometries (wide-block, experts-per-block, token-group; boundaries
at M=4/5, odd/even, M=15/16) are exercised on Blackwell, and the legacy
128/1 geometry everywhere else.
"""
import pytest
import torch
from vllm._custom_ops import fp32_router_gemm
# (hidden_size, num_experts)
SHAPES = [(3072, 256), (6144, 128), (6144, 256)]
ALL_M = list(range(1, 33))
# Absolute tolerance for fp32 kernel vs float64 reference
ATOL_FP32 = 2e-4
ATOL_BF16 = 2e-2 # bf16 activation has lower precision
def _requires_sm90():
if not torch.cuda.is_available():
pytest.skip("CUDA not available")
major, minor = torch.cuda.get_device_capability()
if major * 10 + minor < 90:
pytest.skip(f"fp32_router_gemm requires SM90+, got SM{major}{minor}")
def _ref(mat_a: torch.Tensor, mat_b: torch.Tensor) -> torch.Tensor:
"""Reference: F.linear in float32 on GPU."""
return torch.nn.functional.linear(mat_a.float(), mat_b.float())
@pytest.mark.parametrize("hidden_dim,num_experts", SHAPES)
@pytest.mark.parametrize("num_tokens", ALL_M)
def test_fp32_activation(num_tokens: int, hidden_dim: int, num_experts: int):
"""fp32 activation → fp32 output should match reference closely."""
_requires_sm90()
torch.manual_seed(42)
device = torch.device("cuda")
mat_a = torch.randn(num_tokens, hidden_dim, dtype=torch.float32, device=device)
mat_b = torch.randn(num_experts, hidden_dim, dtype=torch.float32, device=device)
out = fp32_router_gemm(mat_a, mat_b)
ref = _ref(mat_a, mat_b)
assert out.shape == (num_tokens, num_experts)
assert out.dtype == torch.float32
torch.testing.assert_close(out, ref, atol=ATOL_FP32, rtol=0)
@pytest.mark.parametrize("hidden_dim,num_experts", SHAPES)
@pytest.mark.parametrize("num_tokens", ALL_M)
def test_bf16_activation(num_tokens: int, hidden_dim: int, num_experts: int):
"""bf16 activation → fp32 output should match reference within bf16 error."""
_requires_sm90()
torch.manual_seed(42)
device = torch.device("cuda")
mat_a_bf16 = torch.randn(
num_tokens, hidden_dim, dtype=torch.bfloat16, device=device
)
mat_b = torch.randn(num_experts, hidden_dim, dtype=torch.float32, device=device)
out = fp32_router_gemm(mat_a_bf16, mat_b)
ref = _ref(mat_a_bf16, mat_b).to(device)
assert out.shape == (num_tokens, num_experts)
assert out.dtype == torch.float32
torch.testing.assert_close(out, ref, atol=ATOL_BF16, rtol=0)
@pytest.mark.parametrize("hidden_dim,num_experts", SHAPES)
def test_output_shape_and_dtype(hidden_dim: int, num_experts: int):
"""Basic shape and dtype checks."""
_requires_sm90()
device = torch.device("cuda")
mat_a = torch.randn(4, hidden_dim, dtype=torch.float32, device=device)
mat_b = torch.randn(num_experts, hidden_dim, dtype=torch.float32, device=device)
out = fp32_router_gemm(mat_a, mat_b)
assert out.shape == (4, num_experts)
assert out.dtype == torch.float32
assert out.device.type == "cuda"
@pytest.mark.parametrize("hidden_dim,num_experts", SHAPES)
@pytest.mark.parametrize("num_tokens", [1, 2, 4, 8, 16, 24, 32])
def test_topk_routing_consistency(num_tokens: int, hidden_dim: int, num_experts: int):
"""The gate feeds top-k expert selection: the kernel's top-8 must match
an fp64 reference's top-8 per token (ties tolerated). This is the
business-level correctness of the router — numeric error only matters
if it flips the argsort."""
_requires_sm90()
top_k = 8
device = torch.device("cuda")
for seed in range(5):
torch.manual_seed(1000 + seed)
mat_a = torch.randn(num_tokens, hidden_dim, dtype=torch.bfloat16, device=device)
mat_b = torch.randn(num_experts, hidden_dim, dtype=torch.float32, device=device)
out = fp32_router_gemm(mat_a, mat_b)
ref = mat_a.double() @ mat_b.double().t()
kernel_idx = out.topk(top_k, dim=-1).indices
ref_vals, ref_idx = ref.topk(top_k, dim=-1)
for t in range(num_tokens):
got = set(kernel_idx[t].tolist())
want = set(ref_idx[t].tolist())
if got == want:
continue
# Tolerate genuine near-ties around the k-th value only.
kth = ref_vals[t, -1].item()
for e in got.symmetric_difference(want):
gap = abs(ref[t, e].item() - kth)
assert gap < 1e-3, (
f"top-{top_k} mismatch beyond tie tolerance: token {t}, "
f"expert {e}, gap {gap:.3e}"
)
def test_zero_tokens_returns_empty():
"""M=0 is a graceful no-op returning an empty [0, E] tensor."""
_requires_sm90()
device = torch.device("cuda")
hidden_dim, num_experts = SHAPES[0]
mat_a = torch.empty(0, hidden_dim, dtype=torch.float32, device=device)
mat_b = torch.randn(num_experts, hidden_dim, dtype=torch.float32, device=device)
out = fp32_router_gemm(mat_a, mat_b)
assert out.shape == (0, num_experts)
assert out.dtype == torch.float32
def test_rejects_invalid_inputs():
"""The entry must fail loudly, never compute silently wrong results."""
_requires_sm90()
device = torch.device("cuda")
hidden_dim, num_experts = SHAPES[0]
mat_b = torch.randn(num_experts, hidden_dim, dtype=torch.float32, device=device)
# num_tokens > 32 (beyond the instantiated range)
with pytest.raises(Exception, match="num_tokens"):
fp32_router_gemm(
torch.randn(33, hidden_dim, dtype=torch.float32, device=device), mat_b
)
# unsupported (hidden_dim, num_experts) pair
with pytest.raises(Exception, match="supported"):
fp32_router_gemm(
torch.randn(4, 1024, dtype=torch.float32, device=device),
torch.randn(64, 1024, dtype=torch.float32, device=device),
)
# non-contiguous activation (a column-slice view)
wide = torch.randn(4, hidden_dim * 2, dtype=torch.float32, device=device)
with pytest.raises(Exception, match="contiguous"):
fp32_router_gemm(wide[:, :hidden_dim], mat_b)
# wrong weight dtype (bf16 weight is not a supported layout)
with pytest.raises(Exception, match="float32"):
fp32_router_gemm(
torch.randn(4, hidden_dim, dtype=torch.float32, device=device),
mat_b.to(torch.bfloat16),
)
# fp16 activation (only fp32 / bf16 are accepted)
with pytest.raises(Exception, match="float32 or bfloat16"):
fp32_router_gemm(
torch.randn(4, hidden_dim, dtype=torch.float16, device=device), mat_b
)