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sglang/python/sglang/jit_kernel/flash_attention/cute/hopper_helpers.py
2026-01-24 15:25:03 +08:00

102 lines
3.5 KiB
Python

# Copyright (c) 2025, Tri Dao.
from typing import Type, Union, Optional
import cutlass
import cutlass.cute as cute
from cutlass import Int32, Float32, Boolean, const_expr
from cutlass.cute.nvgpu import warpgroup
from cutlass.cutlass_dsl import Numeric, dsl_user_op
from cutlass.utils import LayoutEnum
import cutlass.utils.hopper_helpers as sm90_utils_og
@cute.jit
def gemm(
tiled_mma: cute.TiledMma,
acc: cute.Tensor,
tCrA: cute.Tensor,
tCrB: cute.Tensor,
zero_init: cutlass.Constexpr[bool] = False,
wg_wait: cutlass.Constexpr[int] = 0,
# A_in_regs: cutlass.Constexpr[bool] = False,
swap_AB: cutlass.Constexpr[bool] = False,
) -> None:
if const_expr(swap_AB):
gemm(tiled_mma, acc, tCrB, tCrA, zero_init=zero_init, wg_wait=wg_wait, swap_AB=False)
else:
warpgroup.fence()
# We make a new mma_atom since we'll be modifying its attribute (accumulate).
# Otherwise the compiler complains "operand #0 does not dominate this use"
mma_atom = cute.make_mma_atom(tiled_mma.op)
mma_atom.set(warpgroup.Field.ACCUMULATE, not zero_init)
for k in cutlass.range_constexpr(cute.size(tCrA.shape[2])):
cute.gemm(mma_atom, acc, tCrA[None, None, k], tCrB[None, None, k], acc)
mma_atom.set(warpgroup.Field.ACCUMULATE, True)
warpgroup.commit_group()
if const_expr(wg_wait >= 0):
warpgroup.wait_group(wg_wait)
def gemm_zero_init(
tiled_mma: cute.TiledMma,
shape: cute.Shape,
tCrA: cute.Tensor,
tCrB: cute.Tensor,
A_idx: Optional[Int32] = None,
B_idx: Optional[Int32] = None,
wg_wait: int = -1,
swap_AB: bool = False,
) -> cute.Tensor:
if const_expr(swap_AB):
return gemm_zero_init(
tiled_mma, shape[::-1], tCrB, tCrA, B_idx, A_idx, wg_wait, swap_AB=False
)
else:
acc = cute.make_fragment(tiled_mma.partition_shape_C(shape), Float32)
rA = tCrA if const_expr(A_idx is None) else tCrA[None, None, None, A_idx]
rB = tCrB if const_expr(B_idx is None) else tCrB[None, None, None, B_idx]
gemm(tiled_mma, acc, rA, rB, zero_init=True, wg_wait=wg_wait)
return acc
def gemm_w_idx(
tiled_mma: cute.TiledMma,
acc: cute.Tensor,
tCrA: cute.Tensor,
tCrB: cute.Tensor,
zero_init: Boolean,
A_idx: Optional[Int32] = None,
B_idx: Optional[Int32] = None,
wg_wait: int = -1,
swap_AB: bool = False,
) -> None:
if const_expr(swap_AB):
gemm_w_idx(tiled_mma, acc, tCrB, tCrA, zero_init, B_idx, A_idx, wg_wait, swap_AB=False)
else:
rA = tCrA if const_expr(A_idx is None) else tCrA[None, None, None, A_idx]
rB = tCrB if const_expr(B_idx is None) else tCrB[None, None, None, B_idx]
gemm(tiled_mma, acc, rA, rB, zero_init=zero_init, wg_wait=wg_wait)
@dsl_user_op
def make_smem_layout(
dtype: Type[Numeric],
layout: LayoutEnum,
shape: cute.Shape,
stage: Optional[int] = None,
*,
loc=None,
ip=None,
) -> Union[cute.Layout, cute.ComposedLayout]:
major_mode_size = shape[1] if layout.is_n_major_c() else shape[0]
smem_layout_atom = warpgroup.make_smem_layout_atom(
sm90_utils_og.get_smem_layout_atom(layout, dtype, major_mode_size),
dtype,
)
order = (1, 0, 2) if const_expr(layout.is_m_major_c()) else (0, 1, 2)
smem_layout_staged = cute.tile_to_shape(
smem_layout_atom,
cute.append(shape, stage) if const_expr(stage is not None) else shape,
order=order if const_expr(stage is not None) else order[:2],
)
return smem_layout_staged