sglang_v0.5.2/sglang/sgl-kernel/tests/test_cutlass_mla.py

105 lines
3.4 KiB
Python

import pytest
import torch
import torch.nn.functional as F
from sgl_kernel import cutlass_mla_decode, cutlass_mla_get_workspace_size
from torch import Tensor
# Disable tests on SM103 until the accuracy issues are fixed.
if torch.cuda.get_device_capability() != (10, 0):
pytest.skip(
reason="Cutlass MLA Requires compute capability of 10.",
allow_module_level=True,
)
def ref_mla(
out: Tensor, # (bs, num_heads, v_head_dim)
query: Tensor, # (bs, num_heads, head_dim)
kv_cache: Tensor, # (num_blocks, block_size, head_dim)
scale: float,
block_tables: Tensor, # (bs, max_num_blocks)
seq_lens: Tensor, # (bs,)
):
bs, num_heads, v_head_dim = out.shape
head_dim = query.shape[2]
for i in range(bs):
# gather and flatten KV-cache
kv = kv_cache[block_tables[i]] # (max_num_blocks, block_size, head_dim)
kv = kv.view(1, -1, head_dim)[:, : seq_lens[i]] # (1, seq_len, head_dim)
v = kv[:, :, :v_head_dim]
q = query[i].view(num_heads, 1, head_dim)
o = F.scaled_dot_product_attention(q, kv, v, scale=scale, enable_gqa=True)
out[i] = o.view(num_heads, v_head_dim)
return out
@pytest.mark.parametrize("dtype", [torch.bfloat16, torch.float16])
@pytest.mark.parametrize("mean_seq_len", [128, 1024, 4096])
@pytest.mark.parametrize("bs", [1, 2, 4])
@pytest.mark.parametrize("varlen", [False, True])
@pytest.mark.parametrize("block_size", [1, 16, 64, 128])
@pytest.mark.parametrize("num_heads", [16, 32, 64, 128])
@pytest.mark.parametrize("num_kv_splits", [-1, 1])
def test_cutlass_mla_decode(
dtype: torch.dtype,
mean_seq_len: int,
bs: int,
varlen: bool,
block_size: int,
num_heads: int,
num_kv_splits: int,
):
torch.set_default_dtype(dtype)
torch.set_default_device("cuda")
torch.manual_seed(42)
d = 576
h_q = num_heads
dv = 512
q_nope_dim = 128
q_pe_dim = 64
scale = (q_nope_dim + q_pe_dim) ** (-0.5)
if varlen:
seq_lens = torch.empty(bs).normal_(mean_seq_len, mean_seq_len / 2)
seq_lens = seq_lens.clip(2).to(torch.int32)
else:
seq_lens = torch.full((bs,), mean_seq_len, dtype=torch.int32)
max_seq_len = seq_lens.max().item()
block_num = (max_seq_len + block_size - 1) // block_size
# Pad block_num so that small blocks can be packed into full 128-sized CUTLASS tiles.
# One 128-wide tile can hold (128 // block_size) small blocks.
pack_factor = 128 // block_size
block_num = ((block_num + pack_factor - 1) // pack_factor) * pack_factor
# Lager q values to detect split kv error
q = torch.randn(bs, h_q, d) * 100.0
block_table = torch.randint(0, bs * block_num, (bs, block_num), dtype=torch.int32)
kv_cache = torch.randn(block_table.numel(), block_size, d)
workspace_size = cutlass_mla_get_workspace_size(
block_num * block_size, bs, num_kv_splits=num_kv_splits
)
workspace = torch.empty(workspace_size, device="cuda", dtype=torch.uint8)
q_nope = torch.empty((h_q, bs, dv)).transpose(0, 1)
q_nope.copy_(q[:, :, :dv])
q_pe = q[:, :, dv:].clone()
out_ref = q.new_zeros(bs, h_q, dv)
ref_mla(out_ref, q, kv_cache, scale, block_table, seq_lens)
out = cutlass_mla_decode(
q_nope, q_pe, kv_cache, seq_lens, block_table, workspace, scale, num_kv_splits
)
torch.testing.assert_close(out, out_ref, atol=1e-2, rtol=1e-2)
if __name__ == "__main__":
pytest.main([__file__])