Files
sglang/sgl-kernel/python/sgl_kernel/attention.py
2025-04-11 22:16:51 -07:00

69 lines
2.4 KiB
Python

import torch
def lightning_attention_decode(q, k, v, past_kv, slope, output, new_kv):
torch.ops.sgl_kernel.lightning_attention_decode.default(
q, k, v, past_kv, slope, output, new_kv
)
def cutlass_mla_decode(
q_nope_and_q_pe: torch.Tensor,
kv_c_and_k_pe_cache: torch.Tensor,
seq_lens: torch.Tensor,
page_table: torch.Tensor,
workspace: torch.Tensor,
) -> torch.Tensor:
assert (
q_nope_and_q_pe.ndim == 3
), f"q_nope_and_q_pe must be a 3D tensor, but got {q_nope_and_q_pe.ndim}"
assert (
kv_c_and_k_pe_cache.ndim == 3
), f"kv_c_and_k_pe_cache must be a 3D tensor, but got {kv_c_and_k_pe_cache.ndim}"
B_q, H, D_q = q_nope_and_q_pe.shape
_, PAGE_SIZE, D_ckv = kv_c_and_k_pe_cache.shape
D_latent = 512
D_rope = 64
assert D_q == D_ckv and D_q == D_latent + D_rope, (
f"D_q must be equal to D_ckv and D_q must be equal to D_latent + D_rope, "
f"but got D_q = {D_q}, D_ckv = {D_ckv}, D_latent = {D_latent}, D_rope = {D_rope}"
)
assert H == 128, f"H must be 128, but got {H}"
# TODO: There is currently an illegal memory access issue with page size !=
# 128. Change this when it is fixed.
assert PAGE_SIZE == 128, f"PAGE_SIZE must be 128, but got {PAGE_SIZE}"
# TODO(kaixih@nvidia): support fp8
assert q_nope_and_q_pe.dtype in (
torch.float16,
torch.bfloat16,
), f"q_nope_and_q_pe.dtype needs to be fp16 or bf16 but got {q_nope_and_q_pe.dtype}."
assert kv_c_and_k_pe_cache.dtype == q_nope_and_q_pe.dtype, (
f"kv_c_and_k_pe_cache.dtype needs to be the same as q_nope_and_q_pe.dtype, "
f"but got {kv_c_and_k_pe_cache.dtype}."
)
assert (
seq_lens.dtype == torch.int32
), f"seq_lens.dtype needs to be int32 but got {seq_lens.dtype}."
assert (
page_table.dtype == torch.int32
), f"page_table.dtype needs to be int32 but got {page_table.dtype}."
out = torch.empty(
(B_q, H, D_latent), device=q_nope_and_q_pe.device, dtype=q_nope_and_q_pe.dtype
)
torch.ops.sgl_kernel.cutlass_mla_decode(
out, q_nope_and_q_pe, kv_c_and_k_pe_cache, seq_lens, page_table, workspace
)
return out
def cutlass_mla_get_workspace_size(
max_seq_len: int, num_batches: int, sm_count: int = 0
) -> int:
return torch.ops.sgl_kernel.cutlass_mla_get_workspace_size(
max_seq_len, num_batches, sm_count
)