[GDN] Support SM100 CuTeDSL GDN Prefill Kernel (#26200)

Co-authored-by: luoyuan.luo <luoyuan.luo@antgroup.com>
This commit is contained in:
Yuan Luo
2026-05-26 15:38:29 +08:00
committed by GitHub
co-authored by luoyuan.luo
parent 64c7c6851b
commit d34d4d9f5f
11 changed files with 3766 additions and 9 deletions
@@ -0,0 +1,135 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# Adapted from https://github.com/vllm-project/vllm/blob/4868b542c9dfd166662eecc4bb8be3a36a3feaa2/vllm/cute_utils/__init__.py
from cutlass import BFloat16, Float32, Int64, Uint32, cute
from cutlass._mlir import ir
from cutlass._mlir.dialects import llvm, vector
from cutlass.cute.nvgpu import cpasync
from cutlass.cutlass_dsl import T, dsl_user_op
# https://github.com/NVIDIA/cutlass/blob/v4.3.2/include/cute/arch/copy_sm90_desc.hpp#L193-L197
EVICT_NORMAL = Int64(0x1000000000000000)
EVICT_FIRST = Int64(0x12F0000000000000)
EVICT_LAST = Int64(0x14F0000000000000)
@dsl_user_op
def recast_val(x, dtype, *, loc=None, ip=None):
return dtype(llvm.bitcast(dtype.mlir_type, x.ir_value(loc=loc, ip=ip)))
def simple_tma_copy(atom, src, dst, mbar=None, cache_policy=None):
"""A simple helper that wraps group_modes() and tma_partition()
NOTE: this should be called WITHOUT cute.elect_one()
"""
if isinstance(atom.op, cpasync.CopyBulkTensorTileG2SOp):
gmem = src
smem = dst
elif isinstance(atom.op, cpasync.CopyBulkTensorTileS2GOp):
smem = src
gmem = dst
else:
raise ValueError
s_part, g_part = cpasync.tma_partition(
atom,
0,
cute.make_layout(1),
cute.group_modes(smem, 0),
cute.group_modes(gmem, 0),
)
if isinstance(atom.op, cpasync.CopyBulkTensorTileG2SOp):
cute.copy(atom, g_part, s_part, tma_bar_ptr=mbar, cache_policy=cache_policy)
elif isinstance(atom.op, cpasync.CopyBulkTensorTileS2GOp):
cute.copy(atom, s_part, g_part, cache_policy=cache_policy)
else:
raise ValueError
# can't find the equivalent in nvvm
@dsl_user_op
def fence_before_tma_store(*, loc=None, ip=None):
llvm.inline_asm(
T.i32(),
[],
"mov.u32 $0, 0;\n\t"
"fence.proxy.async::generic.release.sync_restrict::shared::cta.cluster;",
"=r",
has_side_effects=True,
is_align_stack=False,
loc=loc,
ip=ip,
)
@dsl_user_op
def mma_bf16(
a: cute.TensorSSA, b: cute.TensorSSA, c: cute.TensorSSA, *, loc=None, ip=None
):
if a.element_type == BFloat16:
a = cute.recast_tensor(a, Uint32)
if b.element_type == BFloat16:
b = cute.recast_tensor(b, Uint32)
mlir_ty = Float32.mlir_type
out = llvm.inline_asm(
llvm.StructType.get_literal([mlir_ty] * 4),
[a[i].ir_value(loc=loc, ip=ip) for i in range(4)]
+ [b[i].ir_value(loc=loc, ip=ip) for i in range(2)]
+ [c[i].ir_value(loc=loc, ip=ip) for i in range(4)],
"mma.sync.aligned.m16n8k16.row.col.f32.bf16.bf16.f32 "
"{$0, $1, $2, $3}, {$4, $5, $6, $7}, {$8, $9}, "
"{$10, $11, $12, $13};",
"=f,=f,=f,=f,r,r,r,r,r,r,f,f,f,f",
has_side_effects=False,
is_align_stack=False,
loc=loc,
ip=ip,
)
vec = vector.from_elements(
ir.VectorType.get([4], mlir_ty, loc=loc),
[llvm.extractvalue(mlir_ty, out, [i], loc=loc, ip=ip) for i in range(4)],
loc=loc,
ip=ip,
)
return cute.TensorSSA(vec, 4, Float32)
@dsl_user_op
def _bf16x2_abs(a: Uint32, *, loc=None, ip=None) -> Uint32:
out = llvm.inline_asm(
T.i32(),
[a.ir_value(loc=loc, ip=ip)],
"abs.bf16x2 $0, $1;",
"=r,r",
has_side_effects=False,
is_align_stack=False,
)
return Uint32(out)
@dsl_user_op
def _bf16x2_max(a: Uint32, b: Uint32, *, loc=None, ip=None) -> Uint32:
out = llvm.inline_asm(
T.i32(),
[a.ir_value(loc=loc, ip=ip), b.ir_value(loc=loc, ip=ip)],
"max.bf16x2 $0, $1, $2;",
"=r,r,r",
has_side_effects=False,
is_align_stack=False,
)
return Uint32(out)
@dsl_user_op
def _bf16x2_mul(a: Uint32, b: Uint32, *, loc=None, ip=None) -> Uint32:
out = llvm.inline_asm(
T.i32(),
[a.ir_value(loc=loc, ip=ip), b.ir_value(loc=loc, ip=ip)],
"mul.rn.bf16x2 $0, $1, $2;",
"=r,r,r",
has_side_effects=False,
is_align_stack=False,
)
return Uint32(out)
@@ -0,0 +1,220 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# Adapted from https://github.com/vllm-project/vllm/blob/4868b542c9dfd166662eecc4bb8be3a36a3feaa2/vllm/cute_utils/_tcgen05.py
# this module is named _tcgen05 to avoid name collision with cute.nvgpu.tcgen05
import cutlass
from cutlass import Boolean, Float32, Int32, Uint32, Uint64, cute
from cutlass._mlir import ir
from cutlass._mlir.dialects import llvm, nvvm, vector
from cutlass.cutlass_dsl import dsl_user_op
NVVM_CTA_GROUP_MAP = [
None,
nvvm.Tcgen05GroupKind.CTA_1,
nvvm.Tcgen05GroupKind.CTA_2,
]
LDST_MAP = {
"32x32b": (nvvm.Tcgen05LdStShape.SHAPE_32X32B, 1),
"16x128b": (nvvm.Tcgen05LdStShape.SHAPE_16X128B, 2),
"16x256b": (nvvm.Tcgen05LdStShape.SHAPE_16X256B, 4),
}
def _make_tmem_llvm_ptr(addr, *, loc=None, ip=None):
ptr_ty = llvm.PointerType.get(cute.AddressSpace.tmem.value)
val = Int32(addr).ir_value(loc=loc, ip=ip)
return llvm.inttoptr(ptr_ty, val, loc=loc, ip=ip)
@dsl_user_op
def alloc(
taddr: cute.Pointer,
cta_group: int = 1,
*,
loc=None,
ip=None,
) -> None:
nvvm.tcgen05_alloc(
taddr.to_llvm_ptr(loc=loc, ip=ip),
Uint32(512).ir_value(loc=loc, ip=ip),
group=NVVM_CTA_GROUP_MAP[cta_group],
loc=loc,
ip=ip,
)
@dsl_user_op
def dealloc(cta_group: int = 1, *, loc=None, ip=None) -> None:
nvvm.tcgen05_dealloc(
_make_tmem_llvm_ptr(0, loc=loc, ip=ip),
Int32(512).ir_value(loc=loc, ip=ip),
group=NVVM_CTA_GROUP_MAP[cta_group],
loc=loc,
ip=ip,
)
def make_bf16_idesc(
MMA_M: int,
MMA_N: int,
*,
negate_A: bool = False,
negate_B: bool = False,
transpose_A: bool = False,
transpose_B: bool = False,
):
idesc = Uint32(
(1 << 4) | (1 << 7) | (1 << 10) | ((MMA_N >> 3) << 17) | ((MMA_M >> 4) << 24)
)
idesc |= Uint32(negate_A) << 13
idesc |= Uint32(negate_B) << 14
idesc |= Uint32(transpose_A) << 15
idesc |= Uint32(transpose_B) << 16
return idesc
def make_sdesc_128B_swizzle(LBO: int):
SBO = 8 * 128
return Uint64((LBO >> 4 << 16) | (SBO >> 4 << 32) | (1 << 46) | (2 << 61))
@dsl_user_op
def mma_f16(
d_tmem,
a_desc,
b_desc,
idesc,
enable_input_d,
cta_group: int = 1,
*,
loc=None,
ip=None,
) -> None:
nvvm.tcgen05_mma(
nvvm.Tcgen05MMAKind.F16,
NVVM_CTA_GROUP_MAP[cta_group],
_make_tmem_llvm_ptr(d_tmem, loc=loc, ip=ip),
Uint64(a_desc).ir_value(loc=loc, ip=ip),
Uint64(b_desc).ir_value(loc=loc, ip=ip),
Int32(idesc).ir_value(loc=loc, ip=ip),
Boolean(enable_input_d).ir_value(loc=loc, ip=ip),
loc=loc,
ip=ip,
)
@dsl_user_op
def mma_ts_f16(
d_tmem,
a_tmem,
b_desc,
idesc,
enable_input_d,
cta_group: int = 1,
*,
loc=None,
ip=None,
) -> None:
nvvm.tcgen05_mma(
nvvm.Tcgen05MMAKind.F16,
NVVM_CTA_GROUP_MAP[cta_group],
_make_tmem_llvm_ptr(d_tmem, loc=loc, ip=ip),
_make_tmem_llvm_ptr(a_tmem, loc=loc, ip=ip),
Uint64(b_desc).ir_value(loc=loc, ip=ip),
Int32(idesc).ir_value(loc=loc, ip=ip),
Boolean(enable_input_d).ir_value(loc=loc, ip=ip),
loc=loc,
ip=ip,
)
@dsl_user_op
def commit(mbar, cta_mask=None, cta_group: int = 1, *, loc=None, ip=None):
mbar_llvm = mbar.to_llvm_ptr(loc=loc, ip=ip)
group = NVVM_CTA_GROUP_MAP[cta_group]
if cutlass.const_expr(cta_mask is not None):
nvvm.tcgen05_commit_arrive(
mbar_llvm,
multicast_mask=cta_mask.ir_value(loc=loc, ip=ip),
group=group,
loc=loc,
ip=ip,
)
else:
nvvm.tcgen05_commit_arrive(mbar_llvm, group=group, loc=loc, ip=ip)
@dsl_user_op
def ld(row, col, shape: str, num: int, *, loc=None, ip=None):
nvvm_shape, regs_per_num = LDST_MAP[shape]
num_regs = regs_per_num * num
tmem = (Int32(row) << Int32(16)) | Int32(col)
tmem_ptr = _make_tmem_llvm_ptr(tmem, loc=loc, ip=ip)
if num_regs == 1:
reg = nvvm.tcgen05_ld(Int32.mlir_type, nvvm_shape, tmem_ptr, loc=loc, ip=ip)
reg_f32 = llvm.bitcast(Float32.mlir_type, reg, loc=loc, ip=ip)
return Float32(reg_f32)
else:
vec_i32_ty = ir.VectorType.get([num_regs], Int32.mlir_type, loc=loc)
vec_f32_ty = ir.VectorType.get([num_regs], Float32.mlir_type, loc=loc)
regs = nvvm.tcgen05_ld(vec_i32_ty, nvvm_shape, tmem_ptr, loc=loc, ip=ip)
regs_f32 = llvm.bitcast(vec_f32_ty, regs, loc=loc, ip=ip)
return cute.TensorSSA(regs_f32, (num_regs,), Float32)
@dsl_user_op
def st(row, col, shape: str, num: int, vals, *, loc=None, ip=None) -> None:
# if input is TensorSSA, convert to Tensor so we can bitcast
if isinstance(vals, cute.TensorSSA):
vals_ = cute.make_rmem_tensor_like(vals)
vals_.store(vals)
vals = vals_
# bitcast to Int32
vals = cute.recast_tensor(vals, Int32)
nvvm_shape, regs_per_num = LDST_MAP[shape]
num_regs = regs_per_num * num
tmem = (Int32(row) << Int32(16)) | Int32(col)
tmem_ptr = _make_tmem_llvm_ptr(tmem, loc=loc, ip=ip)
if num_regs == 1:
nvvm.tcgen05_st(
nvvm_shape,
tmem_ptr,
vals[0].ir_value(loc=loc, ip=ip),
loc=loc,
ip=ip,
)
else:
vec_i32_ty = ir.VectorType.get([num_regs], Int32.mlir_type, loc=loc)
val_vec = vector.from_elements(
vec_i32_ty,
[vals[i].ir_value(loc=loc, ip=ip) for i in range(num_regs)],
loc=loc,
ip=ip,
)
nvvm.tcgen05_st(nvvm_shape, tmem_ptr, val_vec, loc=loc, ip=ip)
@dsl_user_op
def fence_after_thread_sync(*, loc=None, ip=None):
nvvm.tcgen05_fence(nvvm.Tcgen05FenceKind.AFTER_THREAD_SYNC, loc=loc, ip=ip)
@dsl_user_op
def fence_before_thread_sync(*, loc=None, ip=None):
nvvm.tcgen05_fence(nvvm.Tcgen05FenceKind.BEFORE_THREAD_SYNC, loc=loc, ip=ip)
@dsl_user_op
def wait_ld(*, loc=None, ip=None):
nvvm.tcgen05_wait(nvvm.Tcgen05WaitKind.LOAD, loc=loc, ip=ip)
@dsl_user_op
def wait_st(*, loc=None, ip=None):
nvvm.tcgen05_wait(nvvm.Tcgen05WaitKind.STORE, loc=loc, ip=ip)
@@ -0,0 +1,146 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# Adapted from https://github.com/vllm-project/vllm/blob/4868b542c9dfd166662eecc4bb8be3a36a3feaa2/vllm/cute_utils/cvt.py
from cutlass import Constexpr, Float32, Uint32, cute
from cutlass._mlir import ir
from cutlass._mlir.dialects import llvm, vector
from cutlass.cutlass_dsl import T, dsl_user_op
@dsl_user_op
def fp32x2_to_bf16x2(a: Float32, b: Float32, *, loc=None, ip=None) -> Uint32:
out = llvm.inline_asm(
T.i32(),
[a.ir_value(loc=loc, ip=ip), b.ir_value(loc=loc, ip=ip)],
"cvt.rn.bf16x2.f32 $0, $2, $1;",
"=r,f,f",
has_side_effects=False,
is_align_stack=False,
)
return Uint32(out)
@dsl_user_op
def bf16x2_to_fp32x2(data, *, loc=None, ip=None) -> tuple[Float32, Float32]:
if isinstance(data, Uint32):
out = llvm.inline_asm(
llvm.StructType.get_literal([T.f32(), T.f32()]),
[data.ir_value(loc=loc, ip=ip)],
"shl.b32 $0, $2, 16;\n\tand.b32 $1, $2, 0xFFFF0000;",
"=f,=f,r",
has_side_effects=False,
is_align_stack=False,
loc=loc,
ip=ip,
)
return (
Float32(llvm.extractvalue(T.f32(), out, [0], loc=loc, ip=ip)),
Float32(llvm.extractvalue(T.f32(), out, [1], loc=loc, ip=ip)),
)
elif isinstance(data, (cute.Tensor, cute.TensorSSA)):
# NOTE: the output is always 1D
size = cute.size(data.shape)
out = cute.make_rmem_tensor(size * 2, Float32)
for i in range(size):
out[i * 2], out[i * 2 + 1] = bf16x2_to_fp32x2(data[i])
return out
else:
raise ValueError(f"Unsupported type {type(data)}")
@dsl_user_op
def fp8x4_to_bf16x4(x: Uint32, *, loc=None, ip=None) -> cute.TensorSSA:
# there is only fp8->fp16 conversion, hence we need to go
# round trip through fp16.
out = llvm.inline_asm(
llvm.StructType.get_literal([T.i32()] * 2),
[x.ir_value(loc=loc, ip=ip)],
"{\n\t"
".reg .b16 x0, x1;\n\t"
".reg .b16 t00, t01, t10, t11;\n\t"
"mov.b32 {x0, x1}, $2;\n\t"
"cvt.rn.f16x2.e4m3x2 $0, x0;\n\t"
"cvt.rn.f16x2.e4m3x2 $1, x1;\n\t"
"mov.b32 {t00, t01}, $0;\n\t"
"mov.b32 {t10, t11}, $1;\n\t"
"cvt.rn.bf16.f16 t00, t00;\n\t"
"cvt.rn.bf16.f16 t01, t01;\n\t"
"cvt.rn.bf16.f16 t10, t10;\n\t"
"cvt.rn.bf16.f16 t11, t11;\n\t"
"mov.b32 $0, {t00, t01};\n\t"
"mov.b32 $1, {t10, t11};\n\t"
"}\n",
"=r,=r,r",
has_side_effects=False,
is_align_stack=False,
)
vec = vector.from_elements(
ir.VectorType.get([2], T.i32(), loc=loc),
[llvm.extractvalue(T.i32(), out, [i], loc=loc, ip=ip) for i in range(2)],
loc=loc,
ip=ip,
)
return cute.TensorSSA(vec, 2, Uint32)
@dsl_user_op
def fp32x4_to_fp8x4(
a0: Float32,
a1: Float32,
a2: Float32,
a3: Float32,
*,
loc=None,
ip=None,
) -> Uint32:
# Pack four FP32 values into one b32 of four e4m3 bytes, byte order
# {a0, a1, a2, a3} from low to high address.
out = llvm.inline_asm(
T.i32(),
[
a0.ir_value(loc=loc, ip=ip),
a1.ir_value(loc=loc, ip=ip),
a2.ir_value(loc=loc, ip=ip),
a3.ir_value(loc=loc, ip=ip),
],
"{\n\t"
".reg .b16 t0, t1;\n\t"
"cvt.rn.satfinite.e4m3x2.f32 t0, $2, $1;\n\t"
"cvt.rn.satfinite.e4m3x2.f32 t1, $4, $3;\n\t"
"mov.b32 $0, {t0, t1};\n\t"
"}\n",
"=r,f,f,f,f",
has_side_effects=False,
is_align_stack=False,
)
return Uint32(out)
@dsl_user_op
def fp32x8_to_fp4x8(
vals: cute.Tensor,
offset: Constexpr[int],
*,
loc=None,
ip=None,
) -> Uint32:
# Pack eight scaled FP32 values into four E2M1x2 bytes, returned as one b32.
assert vals.element_type is Float32
out = llvm.inline_asm(
T.i32(),
[vals[offset + i].ir_value(loc=loc, ip=ip) for i in range(8)],
"{\n\t"
".reg .b8 x0, x1, x2, x3;\n\t"
"cvt.rn.satfinite.e2m1x2.f32 x0, $2, $1;\n\t"
"cvt.rn.satfinite.e2m1x2.f32 x1, $4, $3;\n\t"
"cvt.rn.satfinite.e2m1x2.f32 x2, $6, $5;\n\t"
"cvt.rn.satfinite.e2m1x2.f32 x3, $8, $7;\n\t"
"mov.b32 $0, {x0, x1, x2, x3};\n\t"
"}\n",
"=r,f,f,f,f,f,f,f,f",
has_side_effects=False,
is_align_stack=False,
)
return Uint32(out)
@@ -60,6 +60,7 @@ class GDNKernelDispatcher:
):
triton_kernel = TritonGDNKernel()
cutedsl_kernel = None
if decode_backend.is_triton():
self.decode_kernel = triton_kernel
elif decode_backend.is_cutedsl():
@@ -69,7 +70,8 @@ class GDNKernelDispatcher:
CuteDSLGDNKernel,
)
self.decode_kernel = CuteDSLGDNKernel()
cutedsl_kernel = CuteDSLGDNKernel()
self.decode_kernel = cutedsl_kernel
elif decode_backend.is_flashinfer():
if not is_cuda():
raise ValueError("FlashInfer GDN backend requires CUDA")
@@ -85,10 +87,26 @@ class GDNKernelDispatcher:
if prefill_backend.is_triton():
self.extend_kernel = triton_kernel
elif prefill_backend.is_cutedsl():
raise ValueError(
"CuTe DSL backend only supports decode, not prefill. "
"Use --linear-attn-prefill-backend triton instead."
)
if not is_cuda():
raise ValueError("GDN CuTe DSL backend requires CUDA")
# Reuse the CuteDSL kernel if already created for decode
if cutedsl_kernel is None:
from sglang.srt.layers.attention.linear.kernels.gdn_cutedsl import (
CuteDSLGDNKernel,
)
cutedsl_kernel = CuteDSLGDNKernel()
# The CuteDSL prefill kernel only exists on SM100+ (Blackwell).
# On SM90 (Hopper) fall back to Triton so users can pick
# `cutedsl` uniformly across hardware.
if cutedsl_kernel.supports_prefill:
self.extend_kernel = cutedsl_kernel
else:
rank0_log(
"CuTe DSL GDN prefill is not supported on this GPU "
"(requires SM100+). Falling back to Triton for prefill."
)
self.extend_kernel = triton_kernel
elif prefill_backend.is_flashinfer():
if not is_cuda():
raise ValueError("FlashInfer GDN backend requires CUDA")
@@ -0,0 +1,251 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# Adapted from https://github.com/vllm-project/vllm/blob/4868b542c9dfd166662eecc4bb8be3a36a3feaa2/vllm/model_executor/layers/mamba/ops/gdn_chunk_cutedsl/__init__.py
from functools import cache
import cutlass
import torch
import triton
from cuda.bindings.driver import CUstream
from cutlass import Int32, cute
from quack.compile_utils import make_fake_tensor
from .kernel_h import h_cutedsl
from .kernel_kkt_inv_uw import kkt_inv_uw_cutedsl
from .kernel_o import o_cutedsl
class PrepMetaKernel:
def __init__(self, BT: int) -> None:
self.BT = BT
self.num_warps = 8
@cute.jit
def __call__(
self,
cu_seqlens: cute.Tensor,
chunk_indices: cute.Tensor,
chunk_offsets: cute.Tensor,
stream: CUstream,
):
block = (self.num_warps * 32, 1, 1)
self.kernel(
cu_seqlens,
chunk_indices,
chunk_offsets,
).launch(grid=(1, 1, 1), block=block, stream=stream)
@cute.kernel
def kernel(
self,
cu_seqlens: cute.Tensor,
chunk_indices: cute.Tensor,
chunk_offsets: cute.Tensor,
):
tid, _, _ = cute.arch.thread_idx()
warp_id = cute.arch.make_warp_uniform(tid // 32)
lane_id = tid % 32
num_seqs = cu_seqlens.shape[0] - 1
num_warps = self.num_warps
tb_size = num_warps * 32
if tid == 0:
chunk_offsets[0] = 0
coarsen = cute.ceil_div(num_seqs, tb_size)
seq_start = tid * coarsen
num_iters = cutlass.min(seq_start + coarsen, num_seqs) - seq_start
# First pass: compute this thread's total chunk count.
thread_sum = Int32(0)
for i in range(num_iters):
seq_id = seq_start + i
seqlen = cu_seqlens[seq_id + 1] - cu_seqlens[seq_id]
thread_sum += cute.ceil_div(seqlen, self.BT)
# warp parallel scan
cu_num_chunks = thread_sum
for i in cutlass.range_constexpr(5):
offset = cutlass.const_expr(1 << i)
lower = cute.arch.shuffle_sync_up(
cu_num_chunks, offset=offset, mask_and_clamp=0
)
if lane_id >= offset:
cu_num_chunks += lower
# cross-warp cumsum (CTA-wide)
smem = cutlass.utils.SmemAllocator()
warp_num_chunks = smem.allocate_array(Int32, num_warps)
if lane_id == 31:
warp_num_chunks[warp_id] = cu_num_chunks
cute.arch.sync_threads()
for i in cutlass.range_constexpr(1, num_warps):
if warp_id >= i:
cu_num_chunks += warp_num_chunks[i - 1]
chunk_start = cu_num_chunks - thread_sum
# Second pass: recompute per-sequence chunk counts and write results.
for i in range(num_iters):
seq_id = seq_start + i
seqlen = cu_seqlens[seq_id + 1] - cu_seqlens[seq_id]
num_chunks = cute.ceil_div(seqlen, self.BT)
chunk_end = chunk_start + num_chunks
chunk_offsets[seq_id + 1] = chunk_end
for chunk_id in range(num_chunks):
chunk_indices[chunk_start + chunk_id, 0] = seq_id
chunk_indices[chunk_start + chunk_id, 1] = chunk_id
chunk_start = chunk_end
@cache
@staticmethod
def compile(BT: int):
cu_entries = cute.sym_int()
upper_bound_chunks = cute.sym_int()
cu_seqlens = make_fake_tensor(Int32, (cu_entries,), divisibility=1)
chunk_indices = make_fake_tensor(Int32, (upper_bound_chunks, 2), divisibility=2)
chunk_offsets = make_fake_tensor(Int32, (cu_entries,), divisibility=1)
kernel = PrepMetaKernel(BT)
stream = cute.runtime.make_fake_stream(use_tvm_ffi_env_stream=True)
return cute.compile(
kernel,
cu_seqlens,
chunk_indices,
chunk_offsets,
stream,
options="--enable-tvm-ffi",
)
def _upper_bound_chunks(num_seqs: int, total_tokens: int, chunk_size: int) -> int:
return (num_seqs - 1) + triton.cdiv(total_tokens - (num_seqs - 1), chunk_size)
def prepare_metadata_cutedsl(
cu_seqlens: torch.Tensor,
total_tokens: int,
chunk_size: int = 64,
) -> tuple[torch.Tensor, torch.Tensor]:
num_seqs = cu_seqlens.numel() - 1
upper_bound_chunks = _upper_bound_chunks(num_seqs, total_tokens, chunk_size)
chunk_offsets = cu_seqlens.new_empty(num_seqs + 1, dtype=torch.int32)
chunk_indices = cu_seqlens.new_empty((upper_bound_chunks, 2), dtype=torch.int32)
PrepMetaKernel.compile(chunk_size)(cu_seqlens, chunk_indices, chunk_offsets)
return chunk_indices, chunk_offsets
def chunk_gated_delta_rule_cutedsl(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor,
initial_state: torch.Tensor,
cu_seqlens: torch.Tensor,
chunk_indices: torch.Tensor,
chunk_offsets: torch.Tensor,
core_attn_out: torch.Tensor | None = None,
) -> tuple[torch.Tensor, torch.Tensor]:
"""Run the GDN chunk CuteDSL prefill kernels.
Args:
q: Query tensor with shape ``[1, T, H, K]``.
k: Key tensor with shape ``[1, T, H, K]``.
v: Value tensor with shape ``[1, T, Hv, V]``.
g: Log-space decay tensor with shape ``[1, T, Hv]``.
beta: Delta-rule beta tensor with shape ``[1, T, Hv]``.
initial_state: Recurrent state with shape ``[N, Hv, V, K]``.
cu_seqlens: Cumulative sequence lengths with shape ``[N + 1]``.
chunk_indices: Chunk index metadata with shape ``[NT, 2]``.
chunk_offsets: Cumulative chunk offsets with shape ``[N + 1]``.
core_attn_out: Optional output buffer with shape ``[T, Hv, V]``.
Returns:
A tuple ``(output, final_state)`` where ``output`` has shape
``[1, T, Hv, V]`` and ``final_state`` has shape ``[N, Hv, V, K]``.
When ``core_attn_out`` is provided, ``output`` is an unsqueezed view of
that buffer.
"""
q_3d = q.squeeze(0)
k_3d = k.squeeze(0)
v_3d = v.squeeze(0)
g_2d = g.squeeze(0)
beta_2d = beta.squeeze(0)
_, _, head_k_dim = k_3d.shape
_, num_v_heads, head_v_dim = v_3d.shape
chunk_size = 64
upper_bound_chunks = chunk_indices.shape[0]
pad_t = upper_bound_chunks * chunk_size
total_chunks_ptr = chunk_offsets[-1:]
g_cu = torch.empty_like(g_2d, dtype=torch.float32)
u = q_3d.new_empty(pad_t, num_v_heads, head_v_dim)
w = q_3d.new_empty(pad_t, num_v_heads, head_k_dim)
num_sms = torch.cuda.get_device_properties(q.device).multi_processor_count
kkt_inv_uw_cutedsl(
k_3d,
v_3d,
u,
w,
g_2d,
beta_2d,
g_cu,
cu_seqlens,
chunk_indices,
total_chunks_ptr,
num_sms=num_sms,
)
h = k_3d.new_empty(
upper_bound_chunks,
num_v_heads,
head_v_dim,
head_k_dim,
)
v_new = q_3d.new_empty(pad_t, num_v_heads, head_v_dim)
final_state = torch.empty_like(initial_state)
h_cutedsl(
k_3d,
u,
w,
v_new,
g_cu,
h,
initial_state,
final_state,
cu_seqlens,
chunk_offsets,
)
output = core_attn_out if core_attn_out is not None else torch.empty_like(v_3d)
scale = head_k_dim**-0.5
o_cutedsl(
q_3d,
k_3d,
v_new.view(upper_bound_chunks, chunk_size, num_v_heads, head_v_dim),
h,
g_cu,
output,
cu_seqlens,
chunk_indices,
total_chunks_ptr,
scale,
num_sms=num_sms,
)
return output.unsqueeze(0), final_state
__all__ = [
"chunk_gated_delta_rule_cutedsl",
"prepare_metadata_cutedsl",
]
@@ -0,0 +1,754 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# Adapted from https://github.com/vllm-project/vllm/blob/4868b542c9dfd166662eecc4bb8be3a36a3feaa2/vllm/model_executor/layers/mamba/ops/gdn_chunk_cutedsl/kernel_h.py
from functools import cache
import cutlass
import torch
from cuda.bindings.driver import CUstream
from cutlass import BFloat16, Float32, Int32, Int64, Uint32, cute
from cutlass.cute.nvgpu import cpasync, warp
from quack.compile_utils import make_fake_tensor
from sglang.srt.layers.attention.cute_utils import (
EVICT_FIRST,
_tcgen05,
cvt,
fence_before_tma_store,
simple_tma_copy,
)
class Sm100ChunkHKernel:
"""For each sequence, compute the chunk recurrent update.
The input V tile is the U output from the KKT/UW kernel. For each chunk:
V_new = U - W @ H.T
(we actually do V_new.T = U.T - H @ W.T instead)
H_scaled = H * exp(g_last)
V_scaled = V_new * exp(g_last - g)
H_new = H_scaled + V_scaled.T @ K
"""
def __init__(
self,
H: int,
Hv: int,
K_dim: int,
V_dim: int,
h_dtype: cutlass.Numeric = Float32,
BT: int = 64,
num_stages: int = 2,
) -> None:
assert Hv % H == 0
assert K_dim == V_dim == 128
assert BT == 64
self.H = H
self.Hv = Hv
self.K_dim = K_dim
self.V_dim = V_dim
self.h_dtype = h_dtype
self.BT = BT
self.num_stages = num_stages
self.num_warps = 10
@cute.jit
def _make_bf16_tma_args(
self,
tensor: cute.Tensor,
dim: cutlass.Constexpr[int],
op: cpasync.TmaCopyOp,
stages: cutlass.Constexpr[int],
):
swizzle_128B = cute.make_swizzle(3, 4, 3)
slayout = cute.make_layout(
(self.BT, 1, (64, dim // 64), stages),
stride=(64, 0, (1, self.BT * 64), self.BT * dim),
)
slayout = cute.make_composed_layout(swizzle_128B, 0, slayout)
atom, tma_tensor = cpasync.make_tiled_tma_atom(
op,
cute.logical_divide(tensor, (None, None, 64)),
slayout,
cta_tiler=(self.BT, 1, dim),
)
return atom, tma_tensor, slayout
@cute.jit
def _make_h_tma_args(self, tensor: cute.Tensor, op: cpasync.TmaCopyOp):
# number of elements to fill 128B
num_elems = 128 // (tensor.element_type.width // 8)
swizzle_128B = cute.make_swizzle(3, 4, 3)
slayout = cute.make_layout(
(1, 1, self.V_dim, (num_elems, self.K_dim // num_elems)),
stride=(0, 0, num_elems, (1, self.V_dim * num_elems)),
)
slayout = cute.make_composed_layout(swizzle_128B, 0, slayout)
atom, tma_tensor = cpasync.make_tiled_tma_atom(
op,
cute.logical_divide(tensor, (None, None, None, num_elems)),
slayout,
cta_tiler=(1, 1, self.V_dim, self.K_dim),
)
return atom, tma_tensor, slayout
@cute.jit
def __call__(
self,
K: cute.Tensor,
V: cute.Tensor,
W: cute.Tensor,
V_new: cute.Tensor,
g_cu: cute.Tensor,
h: cute.Tensor,
h0: cute.Tensor,
ht: cute.Tensor,
cu_seqlens: cute.Tensor,
chunk_offsets: cute.Tensor,
stream: CUstream,
):
tma_g2s = cpasync.CopyBulkTensorTileG2SOp()
tma_s2g = cpasync.CopyBulkTensorTileS2GOp()
K_args = self._make_bf16_tma_args(K, self.K_dim, tma_g2s, self.num_stages)
V_args = self._make_bf16_tma_args(V, self.V_dim, tma_g2s, self.num_stages)
W_args = self._make_bf16_tma_args(W, self.K_dim, tma_g2s, self.num_stages)
V_new_args = self._make_bf16_tma_args(V_new, self.V_dim, tma_s2g, 1)
H0_args = self._make_h_tma_args(h0, tma_g2s)
HT_args = self._make_h_tma_args(ht, tma_s2g)
H_args = self._make_h_tma_args(h, tma_s2g)
grid = (self.Hv, h0.shape[0], 1)
block = (self.num_warps * 32, 1, 1)
self.kernel(
K_args,
V_args,
W_args,
V_new_args,
H0_args,
HT_args,
H_args,
g_cu,
cu_seqlens,
chunk_offsets,
).launch(grid=grid, block=block, stream=stream)
@cute.kernel
def kernel(
self,
K_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
V_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
W_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
V_new_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
H0_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
HT_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
H_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
g_cu: cute.Tensor,
cu_seqlens: cute.Tensor,
chunk_offsets: cute.Tensor,
):
tid, _, _ = cute.arch.thread_idx()
head_id, seq_id, _ = cute.arch.block_idx()
warp_id = cute.arch.make_warp_uniform(tid // 32)
lane_id = tid % 32
BT = self.BT
V_dim = self.V_dim
K_dim = self.K_dim
num_stages = self.num_stages
is_f32 = self.h_dtype == Float32
K_tma_atom, tmaK, sK_layout = K_args
V_tma_atom, tmaV, sV_layout = V_args
W_tma_atom, tmaW, sW_layout = W_args
V_new_tma_atom, tmaV_new, sV_new_layout = V_new_args
H0_tma_atom, tmaH0, sH0_layout = H0_args
HT_tma_atom, tmaHT, _ = HT_args
H_tma_atom, tmaH, sH_layout = H_args
def allocate_tensor(smem, dtype, layout):
return smem.allocate_tensor(
dtype, layout.outer, byte_alignment=128, swizzle=layout.inner
)
smem = cutlass.utils.SmemAllocator()
# remove size=1 modes
sW = allocate_tensor(smem, BFloat16, sW_layout)[None, 0, None, None]
sV = allocate_tensor(smem, BFloat16, sV_layout)[None, 0, None, None]
sK = allocate_tensor(smem, BFloat16, sK_layout)[None, 0, None, None]
sH0 = allocate_tensor(smem, self.h_dtype, sH0_layout)[0, 0, None, None]
sH = allocate_tensor(smem, BFloat16, sH_layout)[0, 0, None, None]
sV_new = allocate_tensor(smem, BFloat16, sV_new_layout)[None, 0, None, 0]
s_v_scale = smem.allocate_array(Float32, BT)
tma_mbar = smem.allocate_array(Int64, num_stages)
wh_in_mbar = smem.allocate_array(Int64, num_stages)
wh_done_mbar = smem.allocate_array(Int64, num_stages)
vk_in_mbar = smem.allocate_array(Int64, num_stages)
vk_done_mbar = smem.allocate_array(Int64, num_stages)
h0_mbar = smem.allocate_array(Int64, 1)
taddr = smem.allocate(Int32, 4)
wh_tmem = 0
vk_tmem = wh_tmem + BT
h_tmem_base = vk_tmem + K_dim
v_tmem_base = h_tmem_base + K_dim // 2
if warp_id == 0:
with cute.arch.elect_one():
for i in cutlass.range_constexpr(num_stages):
cute.arch.mbarrier_init(tma_mbar + i, 1)
cute.arch.mbarrier_init(wh_in_mbar + i, 256)
cute.arch.mbarrier_init(wh_done_mbar + i, 1)
cute.arch.mbarrier_init(vk_in_mbar + i, 256)
cute.arch.mbarrier_init(vk_done_mbar + i, 1)
cute.arch.mbarrier_init(h0_mbar, 1)
cute.arch.mbarrier_init_fence()
elif warp_id == 1:
cpasync.prefetch_descriptor(H0_tma_atom)
cpasync.prefetch_descriptor(W_tma_atom)
cpasync.prefetch_descriptor(V_tma_atom)
cpasync.prefetch_descriptor(K_tma_atom)
cpasync.prefetch_descriptor(HT_tma_atom)
cpasync.prefetch_descriptor(H_tma_atom)
cpasync.prefetch_descriptor(V_new_tma_atom)
cute.arch.sync_threads()
bos = cu_seqlens[seq_id]
eos = cu_seqlens[seq_id + 1]
seqlen = eos - bos
num_chunks = cute.ceil_div(seqlen, BT)
if warp_id == 9:
# TMA warp
stage_id = 0
parity = 1
k_head_id = head_id // (self.Hv // self.H)
chunk_offset = chunk_offsets[seq_id]
# load H0
with cute.arch.elect_one():
H0_size = V_dim * K_dim * self.h_dtype.width // 8
cute.arch.mbarrier_arrive_and_expect_tx(h0_mbar, H0_size)
simple_tma_copy(
H0_tma_atom, tmaH0[seq_id, head_id, None, None], sH0, h0_mbar
)
# shape: ((BT, num_BT_tiles), (64, 2))
gW_tiles = cute.logical_divide(tmaW[None, head_id, None], (BT, None))
gV_tiles = cute.logical_divide(tmaV[None, head_id, None], (BT, None))
gK_tiles = cute.logical_divide(
cute.domain_offset((bos, 0), tmaK[None, k_head_id, None]),
(BT, None),
)
for chunk_id in range(num_chunks):
mbar = tma_mbar + stage_id
gW = gW_tiles[(None, chunk_offset + chunk_id), None]
gV = gV_tiles[(None, chunk_offset + chunk_id), None]
gK = gK_tiles[(None, chunk_id), None]
# wait for MMA to release the buffer
cute.arch.mbarrier_wait(vk_done_mbar + stage_id, parity)
# load W, V (i.e. U), and K
with cute.arch.elect_one():
STAGE_SIZE = BT * (K_dim + V_dim + K_dim) * 2
cute.arch.mbarrier_arrive_and_expect_tx(mbar, STAGE_SIZE)
simple_tma_copy(
W_tma_atom, gW, sW[None, None, stage_id], mbar, EVICT_FIRST
)
simple_tma_copy(
V_tma_atom, gV, sV[None, None, stage_id], mbar, EVICT_FIRST
)
simple_tma_copy(K_tma_atom, gK, sK[None, None, stage_id], mbar)
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
parity ^= 1
elif warp_id == 8:
# MMA warp
_tcgen05.alloc(taddr)
stage_id = 0
parity = 0
wh_idesc = _tcgen05.make_bf16_idesc(V_dim, BT, negate_A=True)
vk_idesc = _tcgen05.make_bf16_idesc(V_dim, K_dim, transpose_B=True)
# LBO=BT*128 is ignored for K-major
sdesc_template = _tcgen05.make_sdesc_128B_swizzle(BT * 128)
# when using BF16 state, H is read from smem for the 1st iteration
# variable names in this conditional branch can't be the same as those
# in the mainloop below due to CuteDSL restrictions.
if cutlass.const_expr(not is_f32):
##### 1st MMA: V_new.T = V.T - H @ W.T #####
Haddr0 = sH0[None, None].iterator.toint()
Waddr0 = sW[None, None, stage_id].iterator.toint()
hdesc0_base = sdesc_template | (Haddr0 >> 4)
wdesc0_base = sdesc_template | (Waddr0 >> 4)
cute.arch.mbarrier_wait(tma_mbar + stage_id, parity)
cute.arch.mbarrier_wait(wh_in_mbar + stage_id, parity)
_tcgen05.fence_after_thread_sync()
with cute.arch.elect_one():
for i in cutlass.range_constexpr(K_dim // 64):
for j in cutlass.range_constexpr(64 // 16):
hdesc0 = hdesc0_base | ((i * V_dim * 128 + j * 32) >> 4)
wdesc0 = wdesc0_base | ((i * BT * 128 + j * 32) >> 4)
_tcgen05.mma_f16(wh_tmem, hdesc0, wdesc0, wh_idesc, True)
_tcgen05.commit(wh_done_mbar + stage_id)
##### 2nd MMA: H_new = H + V_new.T @ K #####
Kaddr0 = sK[None, None, stage_id].iterator.toint()
kdesc0_base = sdesc_template | (Kaddr0 >> 4)
cute.arch.mbarrier_wait(vk_in_mbar + stage_id, parity)
_tcgen05.fence_after_thread_sync()
with cute.arch.elect_one():
for k in cutlass.range_constexpr(BT // 16):
vtmem0 = v_tmem_base + k * 8
kdesc0 = kdesc0_base | ((k * 16 * 128) >> 4)
_tcgen05.mma_ts_f16(vk_tmem, vtmem0, kdesc0, vk_idesc, True)
_tcgen05.commit(vk_done_mbar + stage_id)
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
parity ^= 1
num_iters = num_chunks - int(not is_f32)
for _ in range(num_iters):
##### 1st MMA: V_new.T = V.T - H @ W.T #####
Waddr = sW[None, None, stage_id].iterator.toint()
wdesc_base = sdesc_template | (Waddr >> 4)
cute.arch.mbarrier_wait(tma_mbar + stage_id, parity)
cute.arch.mbarrier_wait(wh_in_mbar + stage_id, parity)
_tcgen05.fence_after_thread_sync()
with cute.arch.elect_one():
for i in cutlass.range_constexpr(K_dim // 64):
for j in cutlass.range_constexpr(64 // 16):
htmem = h_tmem_base + i * 32 + j * 8
wdesc = wdesc_base | ((i * BT * 128 + j * 32) >> 4)
_tcgen05.mma_ts_f16(wh_tmem, htmem, wdesc, wh_idesc, True)
_tcgen05.commit(wh_done_mbar + stage_id)
##### 2nd MMA: H_new = H + V_new.T @ K #####
Kaddr = sK[None, None, stage_id].iterator.toint()
kdesc_base = sdesc_template | (Kaddr >> 4)
cute.arch.mbarrier_wait(vk_in_mbar + stage_id, parity)
_tcgen05.fence_after_thread_sync()
with cute.arch.elect_one():
for k in cutlass.range_constexpr(BT // 16):
vtmem = v_tmem_base + k * 8
kdesc = kdesc_base | ((k * 16 * 128) >> 4)
_tcgen05.mma_ts_f16(vk_tmem, vtmem, kdesc, vk_idesc, True)
_tcgen05.commit(vk_done_mbar + stage_id)
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
parity ^= 1
elif warp_id >= 4:
# H warps
tid_ = tid % 128
warp_id_ = warp_id % 4
chunk_offset = chunk_offsets[seq_id]
stage_id = 0
vk_stage_id = 0
vk_parity = 0
op = cute.nvgpu.CopyUniversalOp()
cp_16B = cute.make_copy_atom(op, Float32, num_bits_per_copy=128)
##### chunk_id = 0 #####
if True:
chunk_id = 0
end_t = min(bos + (chunk_id + 1) * BT, eos)
last_idx = end_t - 1
h_scale = cute.math.exp(g_cu[last_idx, head_id], fastmath=True)
# for 1st chunk, wait for H0 transfer from gmem
if warp_id_ == 0:
cute.arch.mbarrier_wait(h0_mbar, 0)
cute.arch.barrier(barrier_id=1, number_of_threads=128)
# when H0 is FP32, we need to pack it to BF16
# also store to smem for TMA store later.
if cutlass.const_expr(is_f32):
for i in cutlass.range_constexpr(K_dim // 32):
# H0 smem layout: (V_dim, (32, K_dim/32))
h_f32 = cute.make_rmem_tensor(32, Float32)
cute.copy(cp_16B, sH0[tid_, (None, i)], h_f32)
h_bf16 = cute.make_rmem_tensor(32, BFloat16)
h_bf16.store(h_f32.load().to(BFloat16))
_tcgen05.st(
warp_id_ * 32, h_tmem_base + i * 16, "32x32b", 16, h_bf16
)
# H smem layout: (V_dim, (64, K_dim/64))
dst = cute.local_tile(sH[tid_, None], (32,), (i,))
cute.copy(cp_16B, h_bf16, dst)
_tcgen05.wait_st()
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(wh_in_mbar + stage_id)
# scale H for 2nd MMA
for i in cutlass.range_constexpr(K_dim // 32):
h_f32 = cute.make_rmem_tensor(32, Float32)
if cutlass.const_expr(is_f32):
cute.copy(cp_16B, sH0[tid_, (None, i)], h_f32)
else:
h_bf16 = cute.make_rmem_tensor(32, BFloat16)
sH_src = cute.local_tile(sH0[tid_, None], (32,), (i,))
cute.copy(cp_16B, sH_src, h_bf16)
h_f32.store(
cvt.bf16x2_to_fp32x2(
cute.recast_tensor(h_bf16, Uint32)
).load()
)
for j in cutlass.range_constexpr(32):
h_f32[j] *= h_scale
_tcgen05.st(warp_id_ * 32, vk_tmem + i * 32, "32x32b", 32, h_f32)
_tcgen05.wait_st()
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(vk_in_mbar + stage_id)
# for BF16 H0, we issue TMA store from H0 smem
# for FP32 H0, we issue TMA store from H smem (after packing)
cute.arch.barrier(barrier_id=1, number_of_threads=128)
fence_before_tma_store()
if warp_id_ == 3:
h_src = sH if cutlass.const_expr(is_f32) else sH0
h_dst = tmaH[chunk_offset + chunk_id, head_id, None, None]
simple_tma_copy(H_tma_atom, h_src, h_dst)
with cute.arch.elect_one():
cute.arch.cp_async_bulk_commit_group()
# When H0 is BF16, and there is only 1 chunk, storing
# the final state to sH0 can race before this store
# has finished. hence, we need to wait here.
if cutlass.const_expr(not is_f32):
cute.arch.cp_async_bulk_wait_group(0, read=True)
stage_id = (stage_id + 1) % num_stages
##### subsequent chunks #####
for chunk_id in range(1, num_chunks):
end_t = min(bos + (chunk_id + 1) * BT, eos)
last_idx = end_t - 1
h_scale = cute.math.exp(g_cu[last_idx, head_id], fastmath=True)
# wait for H from previous vk MMA
if warp_id_ == 0:
cute.arch.mbarrier_wait(vk_done_mbar + vk_stage_id, vk_parity)
vk_stage_id = (vk_stage_id + 1) % num_stages
if vk_stage_id == 0:
vk_parity ^= 1
elif warp_id_ == 3:
with cute.arch.elect_one():
cute.arch.cp_async_bulk_wait_group(0, read=True)
cute.arch.barrier(barrier_id=1, number_of_threads=128)
_tcgen05.fence_after_thread_sync()
# load FP32 H from tmem, convert to BF16, store to tmem for 1st MMA,
# store to smem for TMA store later.
for i in cutlass.range_constexpr(K_dim // 32):
h_f32 = _tcgen05.ld(warp_id_ * 32, vk_tmem + i * 32, "32x32b", 32)
h_bf16 = cute.make_rmem_tensor(32, BFloat16)
h_bf16.store(h_f32.to(BFloat16))
_tcgen05.st(
warp_id_ * 32, h_tmem_base + i * 16, "32x32b", 16, h_bf16
)
# H smem layout: (V_dim, (64, K_dim/64))
dst = cute.local_tile(sH[tid_, None], (32,), (i,))
cute.copy(cp_16B, h_bf16, dst)
_tcgen05.wait_st()
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(wh_in_mbar + stage_id)
# scale H for 2nd MMA
for i in cutlass.range_constexpr(K_dim // 32):
h_f32 = cute.make_rmem_tensor(32, Float32)
h_f32.store(
_tcgen05.ld(warp_id_ * 32, vk_tmem + i * 32, "32x32b", 32)
)
for j in cutlass.range_constexpr(32):
h_f32[j] *= h_scale
_tcgen05.st(warp_id_ * 32, vk_tmem + i * 32, "32x32b", 32, h_f32)
_tcgen05.wait_st()
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(vk_in_mbar + stage_id)
# issue TMA store for O kernel
cute.arch.barrier(barrier_id=1, number_of_threads=128)
fence_before_tma_store()
if warp_id_ == 3:
h_dst = tmaH[chunk_offset + chunk_id, head_id, None, None]
simple_tma_copy(H_tma_atom, sH, h_dst)
with cute.arch.elect_one():
cute.arch.cp_async_bulk_commit_group()
stage_id = (stage_id + 1) % num_stages
# handle final state. reuse H0 smem.
if warp_id_ == 0:
cute.arch.mbarrier_wait(vk_done_mbar + vk_stage_id, vk_parity)
cute.arch.barrier(barrier_id=1, number_of_threads=128)
_tcgen05.fence_after_thread_sync()
for i in cutlass.range_constexpr(K_dim // 32):
h_f32 = cute.make_rmem_tensor(32, Float32)
h_f32.store(_tcgen05.ld(warp_id_ * 32, vk_tmem + i * 32, "32x32b", 32))
if cutlass.const_expr(is_f32):
cute.copy(cp_16B, h_f32, sH0[tid_, (None, i)])
else:
h_bf16 = cute.make_rmem_tensor(32, BFloat16)
h_bf16.store(h_f32.load().to(BFloat16))
sH0_dst = cute.local_tile(sH0[tid_, None], (32,), (i,))
cute.copy(cp_16B, h_bf16, sH0_dst)
cute.arch.barrier(barrier_id=1, number_of_threads=128)
if warp_id_ == 0:
ht_dst = tmaHT[seq_id, head_id, None, None]
simple_tma_copy(HT_tma_atom, sH0, ht_dst)
with cute.arch.elect_one():
cute.arch.cp_async_bulk_commit_group()
if warp_id_ == 1:
_tcgen05.dealloc()
else:
# V warps
stage_id = 0
parity = 0
chunk_offset = chunk_offsets[seq_id]
ldsm_trans_op = warp.LdMatrix8x8x16bOp(num_matrices=4, transpose=True)
stsm_trans_op = warp.StMatrix8x8x16bOp(num_matrices=4, transpose=True)
ldsm_trans_atom = cute.make_copy_atom(ldsm_trans_op, BFloat16)
stsm_trans_atom = cute.make_copy_atom(stsm_trans_op, BFloat16)
# ((BT, num_BT_tiles), V_dim)
gV_new_tiles = cute.logical_divide(
tmaV_new[None, head_id, None], (BT, None)
)
# sV shape: [BT, (64, V_dim/64), num_stages]
# sV_view shape: [BT, (8, (8,2)), num_stages]
sV_view = cute.logical_divide(sV, (None, 8, None))
sV_new_view = cute.logical_divide(sV_new, (None, 8))
# [BT, 8, num_stages]
s_col = warp_id * 4 + (lane_id // 8)
sV_view = sV_view[None, (None, s_col), None]
sV_new_view = sV_new_view[None, (None, s_col)]
for chunk_id in range(num_chunks):
# wait for V to arrive
if warp_id == 0:
cute.arch.mbarrier_wait(tma_mbar + stage_id, parity)
cute.arch.barrier(barrier_id=2, number_of_threads=128)
# unpack V BF16->FP32, then store to tmem for 1st MMA
# V smem layout: [BT, (64, V_dim/64)] / [BT, V_dim]
# each iteration, CTA loads [8, V_dim] tile
# (warp loads [8, 32] tile)
for i in cutlass.range_constexpr(BT // 8):
s_row = i * 8 + (lane_id % 8)
v_bf16 = cute.make_rmem_tensor(8, BFloat16)
cute.copy(ldsm_trans_atom, sV_view[s_row, None, stage_id], v_bf16)
v_fp32 = cvt.bf16x2_to_fp32x2(cute.recast_tensor(v_bf16, Uint32))
v_fp32 = cute.logical_divide(v_fp32, 4) # (4, 2)
tcol = wh_tmem + i * 8
_tcgen05.st(warp_id * 32 + 0, tcol, "16x256b", 1, v_fp32[None, 0])
_tcgen05.st(warp_id * 32 + 16, tcol, "16x256b", 1, v_fp32[None, 1])
_tcgen05.wait_st()
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(wh_in_mbar + stage_id)
# load g_cu for scaling
if tid < BT:
end_t = min(bos + (chunk_id + 1) * BT, eos)
last_idx = end_t - 1
t = bos + chunk_id * BT + tid
val = Float32(0.0)
if t < eos:
val = cute.math.exp(
g_cu[last_idx, head_id] - g_cu[t, head_id],
fastmath=True,
)
s_v_scale[tid] = val
# wait for 1st MMA to finish
if warp_id == 2:
cute.arch.mbarrier_wait(wh_done_mbar + stage_id, parity)
elif warp_id == 3:
with cute.arch.elect_one():
cute.arch.cp_async_bulk_wait_group(0, read=True)
cute.arch.barrier(barrier_id=2, number_of_threads=128)
_tcgen05.fence_after_thread_sync()
for i in cutlass.range_constexpr(BT // 8):
v_new = cute.make_rmem_tensor((4, 2), Float32)
tcol = wh_tmem + i * 8
v_new[None, 0].store(
_tcgen05.ld(warp_id * 32 + 0, tcol, "16x256b", 1)
)
v_new[None, 1].store(
_tcgen05.ld(warp_id * 32 + 16, tcol, "16x256b", 1)
)
v_new_bf16 = cute.make_rmem_tensor(8, BFloat16)
v_new_bf16.store(v_new.load().to(BFloat16))
# scale V_new for 2nd MMA
scale0 = s_v_scale[i * 8 + (lane_id % 4) * 2 + 0]
scale1 = s_v_scale[i * 8 + (lane_id % 4) * 2 + 1]
v_scaled = cute.make_rmem_tensor(8, Float32)
for k in cutlass.range_constexpr(4):
v_scaled[k * 2] = v_new[k * 2] * scale0
v_scaled[k * 2 + 1] = v_new[k * 2 + 1] * scale1
v_scaled_bf16 = v_scaled.load().to(BFloat16).reshape((4, 2))
# store V_new BF16 for O kernel
s_row = i * 8 + (lane_id % 8)
cute.copy(stsm_trans_atom, v_new_bf16, sV_new_view[s_row, None])
# store to tmem
tcol = v_tmem_base + i * 4
_tcgen05.st(
warp_id * 32 + 0, tcol, "16x128b", 1, v_scaled_bf16[None, 0]
)
_tcgen05.st(
warp_id * 32 + 16, tcol, "16x128b", 1, v_scaled_bf16[None, 1]
)
_tcgen05.wait_st()
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(vk_in_mbar + stage_id)
# issue TMA store for V_new
cute.arch.barrier(barrier_id=2, number_of_threads=128)
fence_before_tma_store()
if warp_id == 3:
gV = gV_new_tiles[(None, chunk_offset + chunk_id), None]
simple_tma_copy(V_new_tma_atom, sV_new, gV)
with cute.arch.elect_one():
cute.arch.cp_async_bulk_commit_group()
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
parity ^= 1
@cache
@staticmethod
def compile(
H: int,
Hv: int,
K_dim: int,
V_dim: int,
h_dtype: cutlass.Numeric = Float32,
BT: int = 64,
num_stages: int = 2,
):
total_t = cute.sym_int()
pad_t = cute.sym_int()
total_chunks_n = cute.sym_int()
num_sequences = cute.sym_int()
cu_entries = cute.sym_int()
K = make_fake_tensor(BFloat16, (total_t, H, K_dim), divisibility=16)
V = make_fake_tensor(BFloat16, (pad_t, Hv, V_dim), divisibility=16)
W = make_fake_tensor(BFloat16, (pad_t, Hv, K_dim), divisibility=16)
V_new = make_fake_tensor(BFloat16, (pad_t, Hv, V_dim), divisibility=16)
g_cu = make_fake_tensor(Float32, (total_t, Hv), divisibility=4)
h = make_fake_tensor(
BFloat16, (total_chunks_n, Hv, V_dim, K_dim), divisibility=16
)
h0 = make_fake_tensor(
h_dtype, (num_sequences, Hv, V_dim, K_dim), divisibility=16
)
ht = make_fake_tensor(
h_dtype, (num_sequences, Hv, V_dim, K_dim), divisibility=16
)
cu_seqlens = make_fake_tensor(Int32, (cu_entries,), divisibility=1)
chunk_offsets = make_fake_tensor(Int32, (cu_entries,), divisibility=1)
kernel = Sm100ChunkHKernel(H, Hv, K_dim, V_dim, h_dtype, BT, num_stages)
stream = cute.runtime.make_fake_stream(use_tvm_ffi_env_stream=True)
return cute.compile(
kernel,
K,
V,
W,
V_new,
g_cu,
h,
h0,
ht,
cu_seqlens,
chunk_offsets,
stream,
options="--enable-tvm-ffi",
)
def h_cutedsl(
K: torch.Tensor,
V: torch.Tensor,
W: torch.Tensor,
V_new: torch.Tensor,
g_cu: torch.Tensor,
h: torch.Tensor,
h0: torch.Tensor,
ht: torch.Tensor,
cu_seqlens: torch.Tensor,
chunk_offsets: torch.Tensor,
BT: int = 64,
num_stages: int = 2,
) -> None:
"""Compute H/V_new with the same argument order as the CUDA wrapper."""
_, H, K_dim = K.shape
_, Hv, V_dim = V.shape
h_dtype = {
torch.bfloat16: BFloat16,
torch.float32: Float32,
}[h0.dtype]
Sm100ChunkHKernel.compile(H, Hv, K_dim, V_dim, h_dtype, BT, num_stages)(
K,
V,
W,
V_new,
g_cu,
h,
h0,
ht,
cu_seqlens,
chunk_offsets,
)
h_v2b_cutedsl = h_cutedsl
@@ -0,0 +1,823 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# Adapted from https://github.com/vllm-project/vllm/blob/4868b542c9dfd166662eecc4bb8be3a36a3feaa2/vllm/model_executor/layers/mamba/ops/gdn_chunk_cutedsl/kernel_kkt_inv_uw.py
from functools import cache
import cutlass
import torch
from cuda.bindings.driver import CUstream
from cutlass import BFloat16, Float32, Int32, Int64, Uint32, cute
from cutlass.cute.nvgpu import cpasync, warp
from quack.compile_utils import make_fake_tensor
from sglang.srt.layers.attention.cute_utils import (
EVICT_FIRST,
_tcgen05,
cvt,
fence_before_tma_store,
mma_bf16,
simple_tma_copy,
)
class Sm100ChunkUWKernel:
"""Compute per-chunk KKT inverse preprocessing and U/W tiles.
Gamma[i,j] = exp(g_cu[i] - g_cu[j])
A = strictLower(beta * (K @ K.T) * Gamma)
Ai = inverse(I + A)
U = (Ai * beta) @ V
W = (Ai * beta * exp(g_cu)) @ K
"""
def __init__(
self,
H: int,
Hv: int,
K_dim: int,
V_dim: int,
num_stages: int = 2,
) -> None:
assert Hv % H == 0
assert K_dim == V_dim == 128
self.H = H
self.Hv = Hv
self.K_dim = K_dim
self.V_dim = V_dim
self.num_stages = num_stages
# hard-code
self.BT = 64
self.num_warps = 2 + 4 + 4
@cute.jit
def _make_tma_args(
self,
tensor: cute.Tensor,
dim: cutlass.Constexpr[int],
num_stages: int,
op: cpasync.TmaCopyOp,
):
# logical layout: [BT, dim]
# permute for TMA: [dim/64, BT, 64] with swizzling
swizzle_128B = cute.make_swizzle(3, 4, 3)
slayout = cute.make_layout(
(self.BT, 1, (64, dim // 64), num_stages),
stride=(64, 0, (1, self.BT * 64), self.BT * dim),
)
slayout = cute.make_composed_layout(swizzle_128B, 0, slayout)
# we need to convert gmem layout to (T, H, (64, D/64)) for make_tiled_tma_atom()
# to emit a single 4D TMA. otherwise, it will emit (D/64)x 3D TMA.
atom, tma_tensor = cpasync.make_tiled_tma_atom(
op,
cute.logical_divide(tensor, (None, None, 64)),
slayout,
cta_tiler=(self.BT, 1, dim),
)
return atom, tma_tensor, slayout
@cute.jit
def __call__(
self,
K: cute.Tensor,
V: cute.Tensor,
U: cute.Tensor,
W: cute.Tensor,
g: cute.Tensor,
beta: cute.Tensor,
g_cu: cute.Tensor,
cu_seqlens: cute.Tensor,
chunk_indices: cute.Tensor,
total_chunks: cute.Tensor,
num_sms: Int32,
stream: CUstream,
):
tma_g2s = cpasync.CopyBulkTensorTileG2SOp()
tma_s2g = cpasync.CopyBulkTensorTileS2GOp()
K_args = self._make_tma_args(K, self.K_dim, self.num_stages, tma_g2s)
V_args = self._make_tma_args(V, self.V_dim, self.num_stages, tma_g2s)
U_args = self._make_tma_args(U, self.V_dim, 1, tma_s2g)
W_args = self._make_tma_args(W, self.K_dim, 1, tma_s2g)
grid = (num_sms // self.Hv, self.Hv, 1)
block = (self.num_warps * 32, 1, 1)
self.kernel(
K_args,
V_args,
U_args,
W_args,
g,
beta,
g_cu,
cu_seqlens,
chunk_indices,
total_chunks,
).launch(grid=grid, block=block, stream=stream)
@cute.kernel
def kernel(
self,
K_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
V_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
U_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
W_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
g: cute.Tensor,
beta: cute.Tensor,
g_cu: cute.Tensor,
cu_seqlens: cute.Tensor,
chunk_indices: cute.Tensor,
total_chunks: cute.Tensor,
):
tid, _, _ = cute.arch.thread_idx()
bid, head_id, _ = cute.arch.block_idx()
grid_x, _, _ = cute.arch.grid_dim()
warp_id = cute.arch.make_warp_uniform(tid // 32)
lane_id = tid % 32
k_head_id = head_id // (self.Hv // self.H)
BT = self.BT
K_dim = self.K_dim
V_dim = self.V_dim
num_stages = self.num_stages
K_tma_atom, tmaK, sK_layout = K_args
V_tma_atom, tmaV, sV_layout = V_args
U_tma_atom, tmaU, sU_layout = U_args
W_tma_atom, tmaW, sW_layout = W_args
def allocate_tensor(smem, dtype, layout):
return smem.allocate_tensor(
dtype, layout.outer, byte_alignment=128, swizzle=layout.inner
)
smem = cutlass.utils.SmemAllocator()
sK = allocate_tensor(smem, BFloat16, sK_layout)[None, 0, None, None]
sV = allocate_tensor(smem, BFloat16, sV_layout)[None, 0, None, None]
sU = allocate_tensor(smem, BFloat16, sU_layout)[None, 0, None, 0]
sW = allocate_tensor(smem, BFloat16, sW_layout)[None, 0, None, 0]
swizzle_128B = cute.make_swizzle(3, 4, 3)
sA_layout = cute.make_layout((BT, (64, 1)), stride=(64, (1, BT * 64)))
sA_layout = cute.make_composed_layout(swizzle_128B, 0, sA_layout)
sA = allocate_tensor(smem, BFloat16, sA_layout)
sAi = allocate_tensor(smem, BFloat16, sA_layout)
s_beta = smem.allocate_array(Float32, BT)
s_g_cu_exp = smem.allocate_array(Float32, BT)
s_g_cu = smem.allocate_array(Float32, BT)
tma_mbar = smem.allocate_array(Int64, num_stages)
mma_kkt_mbar = smem.allocate_array(Int64, num_stages)
inv_mbar = smem.allocate_array(Int64, num_stages)
mma_u_mbar = smem.allocate_array(Int64, num_stages)
mma_w_mbar = smem.allocate_array(Int64, num_stages)
epi_mbar = smem.allocate_array(Int64, num_stages)
taddr = smem.allocate(Int32, 4)
kkt_tmem = 0
U_tmem_base = kkt_tmem + BT
Ab_tmem_base = U_tmem_base + V_dim * num_stages
assert Ab_tmem_base + (BT // 2) * num_stages <= 512
# prepare ldmatrix/stmatrix ops
ldsm_op = warp.LdMatrix8x8x16bOp(num_matrices=4)
stsm_op = warp.StMatrix8x8x16bOp(num_matrices=4)
ldsm_trans_op = warp.LdMatrix8x8x16bOp(num_matrices=4, transpose=True)
ldsm_atom = cute.make_copy_atom(ldsm_op, BFloat16)
stsm_atom = cute.make_copy_atom(stsm_op, BFloat16)
ldsm_trans_atom = cute.make_copy_atom(ldsm_trans_op, BFloat16)
if warp_id == 0:
with cute.arch.elect_one():
for i in cutlass.range_constexpr(num_stages):
cute.arch.mbarrier_init(tma_mbar + i, 1)
cute.arch.mbarrier_init(mma_kkt_mbar + i, 1)
cute.arch.mbarrier_init(inv_mbar + i, 128)
cute.arch.mbarrier_init(mma_u_mbar + i, 1)
cute.arch.mbarrier_init(mma_w_mbar + i, 1)
cute.arch.mbarrier_init(epi_mbar + i, 128)
cute.arch.mbarrier_init_fence()
elif warp_id == 1:
cpasync.prefetch_descriptor(K_tma_atom)
cpasync.prefetch_descriptor(V_tma_atom)
cpasync.prefetch_descriptor(U_tma_atom)
cpasync.prefetch_descriptor(W_tma_atom)
cute.arch.sync_threads()
num_global_chunks = total_chunks[0]
if warp_id == 9:
# TMA warp
stage_id = 0
parity = 1
for global_chunk_id in range(bid, num_global_chunks, grid_x):
seq_id = chunk_indices[global_chunk_id, 0]
chunk_id = chunk_indices[global_chunk_id, 1]
bos = cu_seqlens[seq_id]
# since off_t is not a multiple of BT, we need to use
# domain_offset() to shift the pointer first.
mbar = tma_mbar + stage_id
gK = cute.local_tile(
cute.domain_offset((bos, 0), tmaK[None, k_head_id, None]),
tiler=(BT, K_dim),
coord=(chunk_id, 0),
)
gV = cute.local_tile(
cute.domain_offset((bos, 0), tmaV[None, head_id, None]),
tiler=(BT, V_dim),
coord=(chunk_id, 0),
)
# when UW MMA is done, K and V TMA buffers are released
cute.arch.mbarrier_wait(mma_u_mbar + stage_id, parity)
with cute.arch.elect_one():
STAGE_SIZE = BT * (K_dim + V_dim) * 2
cute.arch.mbarrier_arrive_and_expect_tx(mbar, STAGE_SIZE)
simple_tma_copy(K_tma_atom, gK, sK[None, None, stage_id], mbar)
simple_tma_copy(
V_tma_atom, gV, sV[None, None, stage_id], mbar, EVICT_FIRST
)
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
parity ^= 1
elif warp_id == 8:
# MMA warp
_tcgen05.alloc(taddr)
stage_id = 0
parity = 0
kkt_idesc = _tcgen05.make_bf16_idesc(BT, BT)
u_idesc = _tcgen05.make_bf16_idesc(BT, V_dim, transpose_B=True)
w_idesc = _tcgen05.make_bf16_idesc(BT, K_dim, transpose_B=True)
# LBO=BT*128 is ignored for K-major
sdesc_template = _tcgen05.make_sdesc_128B_swizzle(BT * 128)
for global_chunk_id in range(bid, num_global_chunks, grid_x):
U_tmem = U_tmem_base + V_dim * stage_id
W_tmem = U_tmem | (16 << 16)
Ab_tmem = Ab_tmem_base + (BT // 2) * stage_id
Abg_tmem = Ab_tmem | (16 << 16)
##### KKT MMA: KKT = K @ K.T #####
kaddr = sK[None, None, stage_id].iterator.toint()
kdesc_base = sdesc_template | (kaddr >> 4)
# wait for TMA data to arrive
# kkt tmem is guaranteed to be free as this is issued
# after the previous kkt's consumer (inv warps)
cute.arch.mbarrier_wait(tma_mbar + stage_id, parity)
_tcgen05.fence_after_thread_sync()
with cute.arch.elect_one():
for i in cutlass.range_constexpr(K_dim // 64):
for j in cutlass.range_constexpr(64 // 16):
kdesc = kdesc_base | ((i * BT * 128 + j * 32) >> 4)
_tcgen05.mma_f16(
kkt_tmem,
kdesc,
kdesc,
kkt_idesc,
(i > 0) or (j > 0),
)
_tcgen05.commit(mma_kkt_mbar + stage_id)
##### U/W MMA: U = Ab @ V, W = Abg @ K #####
vaddr = sV[None, None, stage_id].iterator.toint()
vdesc = sdesc_template | (vaddr >> 4)
kdesc = sdesc_template | (kaddr >> 4)
# wait for epilogue to release tmem buffer
cute.arch.mbarrier_wait(epi_mbar + stage_id, parity ^ 1)
cute.arch.mbarrier_wait(inv_mbar + stage_id, parity)
_tcgen05.fence_after_thread_sync()
with cute.arch.elect_one():
for i in cutlass.range_constexpr(BT // 16):
_tcgen05.mma_ts_f16(
W_tmem, Abg_tmem + i * 8, kdesc, w_idesc, i > 0
)
kdesc += (16 * 128) >> 4
_tcgen05.commit(mma_w_mbar + stage_id)
for i in cutlass.range_constexpr(BT // 16):
_tcgen05.mma_ts_f16(
U_tmem, Ab_tmem + i * 8, vdesc, u_idesc, i > 0
)
vdesc += (16 * 128) >> 4
_tcgen05.commit(mma_u_mbar + stage_id)
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
parity ^= 1
cute.arch.mbarrier_wait(epi_mbar + stage_id, parity ^ 1)
_tcgen05.dealloc()
elif warp_id >= 4:
# inv warps
tid_ = tid % 128
warp_id_ = warp_id % 4
stage_id = 0
parity = 0
# view into (16,16) sub-tiles, then ldmatrix layout
sA_ldsm = cute.logical_divide(sA, (16, cute.make_layout((8, 2))))
sAi_ldsm = cute.logical_divide(sAi, (16, cute.make_layout((8, 2))))
sA_ldsm = sA_ldsm[(lane_id % 16, None), ((None, lane_id // 16), None)]
sAi_ldsm = sAi_ldsm[(lane_id % 16, None), ((None, lane_id // 16), None)]
# init Ai smem buffer with zeros (only the first 48 rows)
for i in cutlass.range_constexpr((BT // 4 * 3) * BT // 128):
idx = i * 128 + tid_
sAi[idx // BT, idx % BT] = BFloat16(0.0)
# indices for ldmatrix layout later
row_indices = cute.make_rmem_tensor((1, 2, 1), Int32)
row_indices[0, 0, 0] = warp_id_ * 16 + (lane_id // 4)
row_indices[0, 1, 0] = warp_id_ * 16 + (lane_id // 4) + 8
row_indices = row_indices.load()
col_indices = cute.make_rmem_tensor((2, 1, 2), Int32)
col_indices[0, 0, 0] = (lane_id % 4) * 2 + 0
col_indices[1, 0, 0] = (lane_id % 4) * 2 + 1
col_indices[0, 0, 1] = (lane_id % 4) * 2 + 8
col_indices[1, 0, 1] = (lane_id % 4) * 2 + 9
col_indices = col_indices.load()
for global_chunk_id in range(bid, num_global_chunks, grid_x):
seq_id = chunk_indices[global_chunk_id, 0]
chunk_id = chunk_indices[global_chunk_id, 1]
bos = cu_seqlens[seq_id]
eos = cu_seqlens[seq_id + 1]
off_t = bos + chunk_id * BT
t = off_t + tid_
##### Phase 1: load g and beta #####
if tid_ < BT:
in_bounds = t < eos
beta_val = beta[t, head_id] if in_bounds else Float32(0.0)
g_val = g[t, head_id] if in_bounds else Float32(0.0)
s_beta[tid_] = beta_val
# compute cumsum(g)
# parallel scan within a warp
for i in cutlass.range_constexpr(5):
offset = cutlass.const_expr(1 << i)
lower = cute.arch.shuffle_sync_up(
g_val, offset, mask_and_clamp=0
)
if lane_id >= offset:
g_val += lower
# store warp sum
if lane_id == 31:
s_g_cu[warp_id_] = g_val
cute.arch.barrier(barrier_id=3, number_of_threads=BT)
# add warp sum from lower warps
for i in cutlass.range_constexpr(1, BT // 32):
if warp_id_ >= i:
g_val += s_g_cu[i - 1]
cute.arch.barrier(barrier_id=3, number_of_threads=BT)
# store g_cu to gmem for H and O kernels
if in_bounds:
g_cu[t, head_id] = g_val
# store g and g_cu to smem for later
s_g_cu[tid_] = g_val
s_g_cu_exp[tid_] = cute.math.exp(g_val) if in_bounds else 0.0
##### Phase 2: A = strictLower(beta * kkt * Gamma) #####
if warp_id_ == 0:
cute.arch.mbarrier_wait(mma_kkt_mbar + stage_id, parity)
cute.arch.barrier(barrier_id=1, number_of_threads=128)
_tcgen05.fence_after_thread_sync()
# tmem 16x256b layout / ldmatrix layout
# mode0 is 8 rows together
# mode1 is top and bottom 8 rows
# mode2 is groups of 16 rows
row_coord = (lane_id // 4, None, warp_id_)
s_beta_view = cute.make_tensor(s_beta, (8, 2, 4))
beta_row = s_beta_view[row_coord].load().reshape((1, 2, 1))
s_g_cu_view = cute.make_tensor(s_g_cu, (8, 2, 4))
g_cu_row = s_g_cu_view[row_coord].load().reshape((1, 2, 1))
# mode0 is 2 consecutive elems
# mode1 is top and bottom 8 rows
# mode2 is next 8 columns
# mode3 is repeating that 16x16 tile pattern
kkt = _tcgen05.ld(kkt_tmem, 0, "16x256b", BT // 8)
kkt = kkt.reshape((2, 2, 2, BT // 16))
for i in cutlass.range_constexpr(BT // 16):
# mode0 is 2 elems next to each other
# mode1 is 4 pairs of elems on 1 row
# mode2 is top and bottom 8 rows
# mode3 is next 16 columns
col_coord = (None, lane_id % 4, None, i)
s_g_cu_view = cute.make_tensor(s_g_cu, (2, 4, 2, BT // 16))
g_cu_col = s_g_cu_view[col_coord].load().reshape((2, 1, 2))
Gamma = cute.math.exp(g_cu_row - g_cu_col, fastmath=True)
A = kkt[None, None, None, i] * beta_row * Gamma
# strict lower mask
# NOTE: for OOB t position, s_beta is filled with zeros.
# hence, we don't need to apply bounds check for columns.
A_masked = cute.where(row_indices > col_indices + i * 16, A, 0.0)
# pack to BF16
# CuteDSL doesn't generate cvt.bf16x2.f32 here for some reasons
packed = cute.make_rmem_tensor(4, Uint32)
packed[0] = cvt.fp32x2_to_bf16x2(
A_masked[0, 0, 0], A_masked[1, 0, 0]
)
packed[1] = cvt.fp32x2_to_bf16x2(
A_masked[0, 1, 0], A_masked[1, 1, 0]
)
packed[2] = cvt.fp32x2_to_bf16x2(
A_masked[0, 0, 1], A_masked[1, 0, 1]
)
packed[3] = cvt.fp32x2_to_bf16x2(
A_masked[0, 1, 1], A_masked[1, 1, 1]
)
# store to smem
cute.copy(
stsm_atom,
cute.recast_tensor(packed, BFloat16),
sA_ldsm[warp_id_, None, i],
)
cute.arch.barrier(barrier_id=1, number_of_threads=128)
##### Phase 3: matrix inverse #####
# we use Newton-Schulz iterations to compute the inverse
# of the four 16x16 diagonal blocks.
# Ai_new = 2 Ai - Ai @ M @ Ai
# where M = I + A
#
# we do this with 2 MMAs:
# 1. -AiM = Ai @ (-M)
# 2. Ai_new = 2 Ai + (-AiM) @ Ai
zeros_f32 = cute.make_rmem_tensor(4, Float32)
zeros_f32.fill(0.0)
def set_diagonal(A: cute.Tensor, lane_id: Int32):
"Set the diagonal to 1s"
if lane_id % 9 == 0:
A[0] = (A[0] & Uint32(0xFFFF0000)) | Uint32(0x00003F80)
A[3] = (A[3] & Uint32(0xFFFF0000)) | Uint32(0x00003F80)
elif lane_id % 9 == 4:
A[0] = (A[0] & Uint32(0x0000FFFF)) | Uint32(0x3F800000)
A[3] = (A[3] & Uint32(0x0000FFFF)) | Uint32(0x3F800000)
Ai_bf16 = cute.make_rmem_tensor(8, BFloat16)
mma_B_bf16 = cute.make_rmem_tensor(8, BFloat16)
M_bf16 = cute.make_rmem_tensor(8, BFloat16)
acc = cute.make_rmem_tensor((4, 2), Float32)
# share the same storage
Ai = cute.recast_tensor(Ai_bf16, Uint32)
mma_B = cute.logical_divide(cute.recast_tensor(mma_B_bf16, Uint32), 2)
M = cute.logical_divide(cute.recast_tensor(M_bf16, Uint32), 2)
# initial guess: Ai = I-A
cute.copy(ldsm_atom, sA_ldsm[warp_id_, None, warp_id_], Ai_bf16)
for i in cutlass.range_constexpr(4):
Ai[i] ^= Uint32(0x80008000) # negate A
set_diagonal(Ai, lane_id)
# (4, 2)
Ai_f32 = cute.logical_divide(cvt.bf16x2_to_fp32x2(Ai), 4)
# M is holding -(I+A), stay constant throughout the iterations
cute.copy(ldsm_trans_atom, sA_ldsm[warp_id_, None, warp_id_], M_bf16)
set_diagonal(M, lane_id)
for i in cutlass.range_constexpr(4):
M[i] ^= Uint32(0x80008000)
# 3 rounds of Newton-Schulz
for _ in cutlass.range_constexpr(3):
# First MMA: -AiM = Ai @ (-M)
cute.copy(stsm_atom, Ai_bf16, sA_ldsm[warp_id_, None, warp_id_])
cute.arch.sync_warp()
acc[None, 0] = mma_bf16(Ai, M[None, 0], zeros_f32)
acc[None, 1] = mma_bf16(Ai, M[None, 1], zeros_f32)
Ai_bf16.store(acc.load().to(BFloat16))
# Second MMA: Ai_new = 2Ai + (-AiM) @ Ai
for j in cutlass.range_constexpr(8):
Ai_f32[j] *= 2.0
cute.copy(
ldsm_trans_atom,
sA_ldsm[warp_id_, None, warp_id_],
mma_B_bf16,
)
Ai_f32[None, 0] = mma_bf16(Ai, mma_B[None, 0], Ai_f32[None, 0])
Ai_f32[None, 1] = mma_bf16(Ai, mma_B[None, 1], Ai_f32[None, 1])
Ai_bf16.store(Ai_f32.load().to(BFloat16))
cute.copy(stsm_atom, Ai_bf16, sAi_ldsm[warp_id_, None, warp_id_])
cute.arch.barrier(barrier_id=1, number_of_threads=128)
# off-diagonal by 1
# Ai[i,i-1] = -Ai[i,i] @ A[i,i-1] @ Ai[i-1,i-1].
if warp_id_ > 0:
neg_Ai = cute.make_rmem_tensor(4, Uint32)
for i in cutlass.range_constexpr(4):
neg_Ai[i] = Ai[i] ^ Uint32(0x80008000)
cute.copy(
ldsm_trans_atom,
sA_ldsm[warp_id_, None, warp_id_ - 1],
mma_B_bf16,
)
acc[None, 0] = mma_bf16(neg_Ai, mma_B[None, 0], zeros_f32)
acc[None, 1] = mma_bf16(neg_Ai, mma_B[None, 1], zeros_f32)
Ai_bf16.store(acc.load().to(BFloat16))
cute.copy(
ldsm_trans_atom,
sAi_ldsm[warp_id_ - 1, None, warp_id_ - 1],
mma_B_bf16,
)
acc[None, 0] = mma_bf16(Ai, mma_B[None, 0], zeros_f32)
acc[None, 1] = mma_bf16(Ai, mma_B[None, 1], zeros_f32)
Ai_bf16.store(acc.load().to(BFloat16))
cute.copy(
stsm_atom,
Ai_bf16,
sAi_ldsm[warp_id_, None, warp_id_ - 1],
)
cute.arch.barrier(barrier_id=1, number_of_threads=128)
# off-diagonal by 2
if warp_id_ < 2:
cute.copy(
ldsm_atom,
sA_ldsm[warp_id_ + 2, None, warp_id_],
Ai_bf16,
)
cute.copy(
ldsm_trans_atom,
sAi_ldsm[warp_id_, None, warp_id_],
mma_B_bf16,
)
acc[None, 0] = mma_bf16(Ai, mma_B[None, 0], zeros_f32)
acc[None, 1] = mma_bf16(Ai, mma_B[None, 1], zeros_f32)
cute.copy(
ldsm_atom,
sA_ldsm[warp_id_ + 2, None, warp_id_ + 1],
Ai_bf16,
)
cute.copy(
ldsm_trans_atom,
sAi_ldsm[warp_id_ + 1, None, warp_id_],
mma_B_bf16,
)
acc[None, 0] = mma_bf16(Ai, mma_B[None, 0], acc[None, 0])
acc[None, 1] = mma_bf16(Ai, mma_B[None, 1], acc[None, 1])
tmp = cute.make_rmem_tensor(8, BFloat16)
tmp.store(acc.load().to(BFloat16))
cute.copy(stsm_atom, tmp, sAi_ldsm[warp_id_ + 2, None, warp_id_])
cute.arch.sync_warp()
cute.copy(
ldsm_atom, sAi_ldsm[warp_id_ + 2, None, warp_id_ + 2], Ai_bf16
)
for i in cutlass.range_constexpr(4):
Ai[i] ^= Uint32(0x80008000)
cute.copy(
ldsm_trans_atom,
sAi_ldsm[warp_id_ + 2, None, warp_id_],
mma_B_bf16,
)
acc[None, 0] = mma_bf16(Ai, mma_B[None, 0], zeros_f32)
acc[None, 1] = mma_bf16(Ai, mma_B[None, 1], zeros_f32)
tmp.store(acc.load().to(BFloat16))
cute.copy(stsm_atom, tmp, sAi_ldsm[warp_id_ + 2, None, warp_id_])
cute.arch.barrier(barrier_id=1, number_of_threads=128)
# off-diagonal by 3
if warp_id_ == 0:
cute.copy(ldsm_atom, sA_ldsm[3, None, 0], Ai_bf16)
cute.copy(ldsm_trans_atom, sAi_ldsm[0, None, 0], mma_B_bf16)
acc[None, 0] = mma_bf16(Ai, mma_B[None, 0], zeros_f32)
acc[None, 1] = mma_bf16(Ai, mma_B[None, 1], zeros_f32)
for i in cutlass.range_constexpr(1, 3):
cute.copy(ldsm_atom, sA_ldsm[3, None, i], Ai_bf16)
cute.copy(ldsm_trans_atom, sAi_ldsm[i, None, 0], mma_B_bf16)
acc[None, 0] = mma_bf16(Ai, mma_B[None, 0], acc[None, 0])
acc[None, 1] = mma_bf16(Ai, mma_B[None, 1], acc[None, 1])
tmp = cute.make_rmem_tensor(8, BFloat16)
tmp.store(acc.load().to(BFloat16))
cute.copy(stsm_atom, tmp, sAi_ldsm[3, None, 0])
cute.arch.sync_warp()
cute.copy(ldsm_atom, sAi_ldsm[3, None, 3], Ai_bf16)
for i in cutlass.range_constexpr(4):
Ai[i] ^= Uint32(0x80008000)
cute.copy(ldsm_trans_atom, sAi_ldsm[3, None, 0], mma_B_bf16)
acc[None, 0] = mma_bf16(Ai, mma_B[None, 0], zeros_f32)
acc[None, 1] = mma_bf16(Ai, mma_B[None, 1], zeros_f32)
tmp.store(acc.load().to(BFloat16))
cute.copy(stsm_atom, tmp, sAi_ldsm[3, None, 0])
##### Phase 4: compute Ab, Abg #####
if warp_id_ == 3:
cute.arch.mbarrier_wait(mma_u_mbar + stage_id, parity ^ 1)
cute.arch.barrier(barrier_id=1, number_of_threads=128)
for i in cutlass.range_constexpr(BT // 16):
cute.copy(ldsm_atom, sAi_ldsm[warp_id_, None, i], Ai_bf16)
col_coord = (None, lane_id % 4, None, i)
s_beta_view = cute.make_tensor(s_beta, (2, 4, 2, BT // 16))
beta_col = s_beta_view[col_coord].load().reshape((2, 1, 2))
s_g_cu_view = cute.make_tensor(s_g_cu_exp, (2, 4, 2, BT // 16))
g_cu_col = s_g_cu_view[col_coord].load().reshape((2, 1, 2))
Ai_f32 = cvt.bf16x2_to_fp32x2(Ai).load().reshape((2, 2, 2))
Ab_f32 = Ai_f32 * beta_col
Ab = Ab_f32.to(BFloat16)
Ab_tmem = Ab_tmem_base + (BT // 2) * stage_id + i * 8
_tcgen05.st(warp_id_ * 32, Ab_tmem, "16x128b", 2, Ab)
Abg_f32 = Ab_f32 * g_cu_col
Abg = Abg_f32.to(BFloat16)
_tcgen05.st(warp_id_ * 32 + 16, Ab_tmem, "16x128b", 2, Abg)
_tcgen05.wait_st()
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(inv_mbar + stage_id)
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
parity ^= 1
elif warp_id < 4:
# epi warps
stage_id = 0
parity = 0
# ((BT, num_global_chunks), V_dim)
gU_tiles = cute.logical_divide(tmaU[None, head_id, None], (BT, None))
gW_tiles = cute.logical_divide(tmaW[None, head_id, None], (BT, None))
# sW shape: [BT, (64, K_dim/64)]
# sW_view shape: [(8, 2), (4, K_dim/64)]
s_row = warp_id * 16 + lane_id % 16 # select the rows of [16,16] tile
sW_view = cute.zipped_divide(
sW[s_row, None],
tiler=cute.make_layout((8, 2)),
)
sU_view = cute.zipped_divide(
sU[s_row, None],
tiler=cute.make_layout((8, 2)),
)
# select the 8 columns within [16,16] tile
sW_view = sW_view[(None, lane_id // 16), None]
sU_view = sU_view[(None, lane_id // 16), None]
for global_chunk_id in range(bid, num_global_chunks, grid_x):
# wait for W MMA + previous TMA store to finish
U_tmem = U_tmem_base + V_dim * stage_id
if warp_id == 0:
cute.arch.mbarrier_wait(mma_w_mbar + stage_id, parity)
elif warp_id == 1:
with cute.arch.elect_one():
cute.arch.cp_async_bulk_wait_group(0, read=True)
cute.arch.barrier(barrier_id=2, number_of_threads=128)
_tcgen05.fence_after_thread_sync()
w_f32 = _tcgen05.ld(warp_id * 32 + 16, U_tmem, "16x256b", K_dim // 8)
_tcgen05.wait_ld()
w_bf16 = cute.make_rmem_tensor((8, K_dim // 16), BFloat16)
w_bf16.store(w_f32.to(BFloat16))
cute.copy(stsm_atom, w_bf16, sW_view)
# wait for U MMA + issue W TMA store
cute.arch.barrier(barrier_id=2, number_of_threads=128)
fence_before_tma_store()
if warp_id == 0:
cute.arch.mbarrier_wait(mma_u_mbar + stage_id, parity)
elif warp_id == 1:
# don't need to commit
simple_tma_copy(
W_tma_atom, sW, gW_tiles[(None, global_chunk_id), None]
)
cute.arch.barrier(barrier_id=2, number_of_threads=128)
_tcgen05.fence_after_thread_sync()
u_f32 = _tcgen05.ld(warp_id * 32, U_tmem, "16x256b", V_dim // 8)
_tcgen05.wait_ld()
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(epi_mbar + stage_id)
u_bf16 = cute.make_rmem_tensor((8, V_dim // 16), BFloat16)
u_bf16.store(u_f32.to(BFloat16))
cute.copy(stsm_atom, u_bf16, sU_view)
cute.arch.barrier(barrier_id=2, number_of_threads=128)
fence_before_tma_store()
if warp_id == 1:
simple_tma_copy(
U_tma_atom, sU, gU_tiles[(None, global_chunk_id), None]
)
with cute.arch.elect_one():
cute.arch.cp_async_bulk_commit_group()
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
parity ^= 1
@cache
@staticmethod
def compile(H: int, Hv: int, K_dim: int, V_dim: int, num_stages: int = 2):
total_t = cute.sym_int()
pad_t = cute.sym_int()
total_chunks_n = cute.sym_int()
num_sequences = cute.sym_int()
K = make_fake_tensor(BFloat16, (total_t, H, K_dim), divisibility=16)
V = make_fake_tensor(BFloat16, (total_t, Hv, V_dim), divisibility=16)
U = make_fake_tensor(BFloat16, (pad_t, Hv, V_dim), divisibility=16)
W = make_fake_tensor(BFloat16, (pad_t, Hv, K_dim), divisibility=16)
g = make_fake_tensor(Float32, (total_t, Hv), divisibility=4)
beta = make_fake_tensor(Float32, (total_t, Hv), divisibility=4)
g_cu = make_fake_tensor(Float32, (total_t, Hv), divisibility=4)
cu_seqlens = make_fake_tensor(Int32, (num_sequences,), divisibility=1)
chunk_indices = make_fake_tensor(Int32, (total_chunks_n, 2), divisibility=2)
total_chunks = make_fake_tensor(Int32, (1,), divisibility=1)
kernel = Sm100ChunkUWKernel(H, Hv, K_dim, V_dim, num_stages)
stream = cute.runtime.make_fake_stream(use_tvm_ffi_env_stream=True)
return cute.compile(
kernel,
K,
V,
U,
W,
g,
beta,
g_cu,
cu_seqlens,
chunk_indices,
total_chunks,
Int32(148),
stream,
options="--enable-tvm-ffi",
)
def kkt_inv_uw_cutedsl(
K: torch.Tensor,
V: torch.Tensor,
U: torch.Tensor,
W: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor,
g_cu: torch.Tensor,
cu_seqlens: torch.Tensor,
chunk_indices: torch.Tensor,
total_chunks: torch.Tensor,
num_sms: int = 148,
) -> None:
_, Hv, V_dim = V.shape
_, H, K_dim = K.shape
Sm100ChunkUWKernel.compile(H, Hv, K_dim, V_dim)(
K,
V,
U,
W,
g,
beta,
g_cu,
cu_seqlens,
chunk_indices,
total_chunks,
num_sms,
)
@@ -0,0 +1,631 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# Adapted from https://github.com/vllm-project/vllm/blob/4868b542c9dfd166662eecc4bb8be3a36a3feaa2/vllm/model_executor/layers/mamba/ops/gdn_chunk_cutedsl/kernel_o.py
from functools import cache
import cutlass
import torch
from cuda.bindings.driver import CUstream
from cutlass import BFloat16, Float32, Int32, Int64, Uint32, cute
from cutlass.cute.nvgpu import cpasync, warp
from quack.compile_utils import make_fake_tensor
from sglang.srt.layers.attention.cute_utils import (
EVICT_FIRST,
_tcgen05,
cvt,
fence_before_tma_store,
simple_tma_copy,
)
class Sm100ChunkOKernel:
"""Compute per-token output from recurrent and intra-chunk terms.
Gamma[i,j] = exp(g_cu[i] - g_cu[j])
P = mask((Q @ K.T) * Gamma)
O = scale * (exp(g_cu) * (Q @ H.T) + P @ V)
"""
def __init__(
self,
H: int,
Hv: int,
K_dim: int,
V_dim: int,
BT: int = 64,
num_stages: int = 2,
) -> None:
assert Hv % H == 0
assert K_dim == 128
assert V_dim == 128
assert BT == 64
self.H = H
self.Hv = Hv
self.K_dim = K_dim
self.V_dim = V_dim
self.BT = BT
self.num_stages = num_stages
self.num_warps = 10
@cute.jit
def _make_bf16_tma_args(
self,
tensor: cute.Tensor,
dim: cutlass.Constexpr[int],
op: cpasync.TmaCopyOp,
stages: cutlass.Constexpr[int],
):
swizzle_128B = cute.make_swizzle(3, 4, 3)
slayout = cute.make_layout(
(self.BT, 1, (64, dim // 64), stages),
stride=(64, 0, (1, self.BT * 64), self.BT * dim),
)
slayout = cute.make_composed_layout(swizzle_128B, 0, slayout)
atom, tma_tensor = cpasync.make_tiled_tma_atom(
op,
cute.logical_divide(tensor, (None, None, 64)),
slayout,
cta_tiler=(self.BT, 1, dim),
)
return atom, tma_tensor, slayout
@cute.jit
def _make_h_tma_args(
self,
tensor: cute.Tensor,
op: cpasync.TmaCopyOp,
stages: cutlass.Constexpr[int],
):
num_elems = 128 // (tensor.element_type.width // 8)
swizzle_128B = cute.make_swizzle(3, 4, 3)
slayout = cute.make_layout(
(1, self.V_dim, (num_elems, self.K_dim // num_elems), stages),
stride=(0, num_elems, (1, self.V_dim * num_elems), self.V_dim * self.K_dim),
)
slayout = cute.make_composed_layout(swizzle_128B, 0, slayout)
atom, tma_tensor = cpasync.make_tiled_tma_atom(
op,
cute.logical_divide(tensor, (None, None, num_elems)),
slayout,
cta_tiler=(1, self.V_dim, self.K_dim),
)
return atom, tma_tensor, slayout
@cute.jit
def __call__(
self,
q: cute.Tensor,
k: cute.Tensor,
v_new_chunks: cute.Tensor,
h: cute.Tensor,
g_cu: cute.Tensor,
o: cute.Tensor,
cu_seqlens: cute.Tensor,
chunk_indices: cute.Tensor,
total_chunks: cute.Tensor,
scale: Float32,
num_sms: Int32,
stream: CUstream,
):
grid = (num_sms // self.Hv, self.Hv, 1)
block = (self.num_warps * 32, 1, 1)
tma_g2s = cpasync.CopyBulkTensorTileG2SOp()
tma_s2g = cpasync.CopyBulkTensorTileS2GOp()
Q_args = self._make_bf16_tma_args(q, self.K_dim, tma_g2s, self.num_stages)
K_args = self._make_bf16_tma_args(k, self.K_dim, tma_g2s, self.num_stages)
V_args = self._make_bf16_tma_args(
v_new_chunks, self.V_dim, tma_g2s, self.num_stages
)
H_args = self._make_h_tma_args(h, tma_g2s, self.num_stages)
O_args = self._make_bf16_tma_args(o, self.V_dim, tma_s2g, 1)
self.kernel(
Q_args,
K_args,
V_args,
H_args,
O_args,
g_cu,
o,
cu_seqlens,
chunk_indices,
total_chunks,
scale,
).launch(grid=grid, block=block, stream=stream)
@cute.kernel
def kernel(
self,
Q_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
K_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
V_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
H_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
O_args: tuple[cute.CopyAtom, cute.Tensor, cute.ComposedLayout],
g_cu: cute.Tensor,
o: cute.Tensor,
cu_seqlens: cute.Tensor,
chunk_indices: cute.Tensor,
total_chunks: cute.Tensor,
scale: Float32,
):
tid, _, _ = cute.arch.thread_idx()
bid, v_head_id, _ = cute.arch.block_idx()
grid_x, _, _ = cute.arch.grid_dim()
warp_id = cute.arch.make_warp_uniform(tid // 32)
lane_id = tid % 32
BT = self.BT
K_dim = self.K_dim
V_dim = self.V_dim
num_stages = self.num_stages
heads_per_qk = self.Hv // self.H
k_head_id = v_head_id // heads_per_qk
num_global_chunks = total_chunks[0]
Q_tma_atom, tmaQ, sQ_layout = Q_args
K_tma_atom, tmaK, sK_layout = K_args
V_tma_atom, tmaV, sV_layout = V_args
H_tma_atom, tmaH, sH_layout = H_args
O_tma_atom, tmaO, sO_layout = O_args
def allocate_tensor(smem, dtype, layout):
return smem.allocate_tensor(
dtype, layout.outer, byte_alignment=128, swizzle=layout.inner
)
smem = cutlass.utils.SmemAllocator()
sQ = allocate_tensor(smem, BFloat16, sQ_layout)[None, 0, None, None]
sK = allocate_tensor(smem, BFloat16, sK_layout)[None, 0, None, None]
sV = allocate_tensor(smem, BFloat16, sV_layout)[None, 0, None, None]
sH = allocate_tensor(smem, BFloat16, sH_layout)[0, None, None, None]
sO = allocate_tensor(smem, BFloat16, sO_layout)[None, 0, None, 0]
s_g_cu = smem.allocate_array(Float32, BT)
qk_full_mbar = smem.allocate_array(Int64, num_stages)
hv_full_mbar = smem.allocate_array(Int64, num_stages)
qk_empty_mbar = smem.allocate_array(Int64, num_stages)
pv_mma_mbar = smem.allocate_array(Int64, num_stages)
qk_mbar = smem.allocate_array(Int64, 1)
mask_mbar = smem.allocate_array(Int64, 1)
epi_mbar = smem.allocate_array(Int64, 1)
taddr = smem.allocate(Int32, 4)
qk_tmem = 0
p_tmem = 64
out_tmem = 128
qh_tmem = 256
if warp_id == 0:
with cute.arch.elect_one():
for i in cutlass.range_constexpr(num_stages):
cute.arch.mbarrier_init(qk_full_mbar + i, 1)
cute.arch.mbarrier_init(qk_empty_mbar + i, 1)
cute.arch.mbarrier_init(hv_full_mbar + i, 1)
cute.arch.mbarrier_init(pv_mma_mbar + i, 1)
cute.arch.mbarrier_init(qk_mbar, 1)
cute.arch.mbarrier_init(mask_mbar, 128)
cute.arch.mbarrier_init(epi_mbar, 128)
cute.arch.mbarrier_init_fence()
elif warp_id == 9:
cpasync.prefetch_descriptor(Q_tma_atom)
cpasync.prefetch_descriptor(K_tma_atom)
cpasync.prefetch_descriptor(V_tma_atom)
cpasync.prefetch_descriptor(H_tma_atom)
cute.arch.sync_threads()
if warp_id == 9:
# TMA warp
stage_id = 0
parity = 1
for global_chunk_id in range(bid, num_global_chunks, grid_x):
seq_id = chunk_indices[global_chunk_id, 0]
chunk_id = chunk_indices[global_chunk_id, 1]
bos = cu_seqlens[seq_id]
# copy Q and K
q_tile = cute.local_tile(
cute.domain_offset((bos, 0), tmaQ[None, k_head_id, None]),
tiler=(BT, K_dim),
coord=(chunk_id, 0),
)
k_tile = cute.local_tile(
cute.domain_offset((bos, 0), tmaK[None, k_head_id, None]),
tiler=(BT, K_dim),
coord=(chunk_id, 0),
)
mbar = qk_full_mbar + stage_id
cute.arch.mbarrier_wait(qk_empty_mbar + stage_id, parity)
with cute.arch.elect_one():
STAGE_SIZE = BT * (K_dim + K_dim) * 2
cute.arch.mbarrier_arrive_and_expect_tx(mbar, STAGE_SIZE)
simple_tma_copy(Q_tma_atom, q_tile, sQ[None, None, stage_id], mbar)
simple_tma_copy(K_tma_atom, k_tile, sK[None, None, stage_id], mbar)
# copy H and V
gH = tmaH[global_chunk_id * self.Hv + v_head_id, None, None]
gV = cute.local_tile(
tmaV[None, v_head_id, None],
tiler=(BT, V_dim),
coord=(global_chunk_id, 0),
)
mbar = hv_full_mbar + stage_id
cute.arch.mbarrier_wait(pv_mma_mbar + stage_id, parity)
with cute.arch.elect_one():
H_STAGE_SIZE = V_dim * K_dim * 2
V_STAGE_SIZE = BT * V_dim * 2
cute.arch.mbarrier_arrive_and_expect_tx(
mbar, H_STAGE_SIZE + V_STAGE_SIZE
)
simple_tma_copy(
H_tma_atom, gH, sH[None, None, stage_id], mbar, EVICT_FIRST
)
simple_tma_copy(
V_tma_atom, gV, sV[None, None, stage_id], mbar, EVICT_FIRST
)
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
parity ^= 1
elif warp_id == 8:
# MMA warp
_tcgen05.alloc(taddr)
# LBO=BT*128 is ignored for K-major
sdesc_template = _tcgen05.make_sdesc_128B_swizzle(BT * 128)
qk_idesc = _tcgen05.make_bf16_idesc(BT, BT)
qh_idesc = _tcgen05.make_bf16_idesc(BT, V_dim)
pv_idesc = _tcgen05.make_bf16_idesc(BT, V_dim, transpose_B=True)
stage_id = 0
tma_parity = 0
mask_parity = 0
for global_chunk_id in range(bid, num_global_chunks, grid_x):
qaddr = sQ[None, None, stage_id].iterator.toint()
kaddr = sK[None, None, stage_id].iterator.toint()
haddr = sH[None, None, stage_id].iterator.toint()
vaddr = sV[None, None, stage_id].iterator.toint()
qdesc_base = sdesc_template | (qaddr >> 4)
kdesc_base = sdesc_template | (kaddr >> 4)
hdesc_base = sdesc_template | (haddr >> 4)
vdesc_base = sdesc_template | (vaddr >> 4)
##### 1st MMA: Q @ K.T #####
# do this first to unblock mask(QK)
cute.arch.mbarrier_wait(epi_mbar, mask_parity ^ 1)
cute.arch.mbarrier_wait(qk_full_mbar + stage_id, tma_parity)
_tcgen05.fence_after_thread_sync()
with cute.arch.elect_one():
for i in cutlass.range_constexpr(K_dim // BT):
for j in cutlass.range_constexpr(BT // 16):
qdesc = qdesc_base | ((i * BT * 128 + j * 32) >> 4)
kdesc = kdesc_base | ((i * BT * 128 + j * 32) >> 4)
_tcgen05.mma_f16(
qk_tmem, qdesc, kdesc, qk_idesc, (i > 0) or (j > 0)
)
_tcgen05.commit(qk_mbar)
##### 2nd MMA: Q @ H.T #####
cute.arch.mbarrier_wait(hv_full_mbar + stage_id, tma_parity)
_tcgen05.fence_after_thread_sync()
with cute.arch.elect_one():
for i in cutlass.range_constexpr(K_dim // BT):
for j in cutlass.range_constexpr(BT // 16):
qdesc = qdesc_base | ((i * BT * 128 + j * 32) >> 4)
hdesc = hdesc_base | ((i * V_dim * 128 + j * 32) >> 4)
_tcgen05.mma_f16(
qh_tmem, qdesc, hdesc, qh_idesc, (i > 0) or (j > 0)
)
_tcgen05.commit(qk_empty_mbar + stage_id)
##### 3rd MMA: P @ V #####
# stalled by mask(QK)
cute.arch.mbarrier_wait(mask_mbar, mask_parity)
_tcgen05.fence_after_thread_sync()
with cute.arch.elect_one():
for i in cutlass.range_constexpr(BT // 16):
vdesc = vdesc_base | ((i * 16 * 128) >> 4)
_tcgen05.mma_ts_f16(
out_tmem, p_tmem + i * 8, vdesc, pv_idesc, i > 0
)
_tcgen05.commit(pv_mma_mbar + stage_id)
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
tma_parity ^= 1
mask_parity ^= 1
# wait for epilogue to finish for deallocation
cute.arch.mbarrier_wait(epi_mbar, mask_parity ^ 1)
_tcgen05.dealloc()
elif warp_id >= 4:
# masking warps
warp_id_ = warp_id % 4
tid_ = tid % 128
row0 = warp_id_ * 16 + lane_id // 4
row1 = row0 + 8
parity = 0
# for ldmatrix layout later
row_indices = cute.make_rmem_tensor(2, Int32)
row_indices[0] = warp_id_ * 16 + lane_id // 4
row_indices[1] = warp_id_ * 16 + lane_id // 4 + 8
row_indices = row_indices.load().reshape((1, 2))
col_indices = cute.make_rmem_tensor(2, Int32)
col_indices[0] = (lane_id % 4) * 2
col_indices[1] = (lane_id % 4) * 2 + 1
col_indices = col_indices.load().reshape((2, 1))
for global_chunk_id in range(bid, num_global_chunks, grid_x):
if tid_ < BT:
seq_id = chunk_indices[global_chunk_id, 0]
chunk_id = chunk_indices[global_chunk_id, 1]
bos = cu_seqlens[seq_id]
eos = cu_seqlens[seq_id + 1]
t_ = bos + chunk_id * BT + tid_
s_g_cu[tid_] = g_cu[t_, v_head_id] if t_ < eos else Float32(0.0)
# wait for QK MMA
if warp_id_ == 0:
cute.arch.mbarrier_wait(qk_mbar, parity)
cute.arch.barrier(barrier_id=1, number_of_threads=128)
_tcgen05.fence_after_thread_sync()
qk = _tcgen05.ld(warp_id_ * 32, qk_tmem, "16x256b", BT // 8)
qk = qk.reshape((2, 2, BT // 8))
_tcgen05.wait_ld()
g_cu_rows = cute.make_rmem_tensor(2, Float32)
g_cu_rows[0] = s_g_cu[row0]
g_cu_rows[1] = s_g_cu[row1]
g_cu_rows = g_cu_rows.load().reshape((1, 2))
for i in cutlass.range_constexpr(BT // 8):
col = i * 8 + (lane_id % 4) * 2
g_cu_cols = cute.make_rmem_tensor(2, Float32)
g_cu_cols[0] = s_g_cu[col]
g_cu_cols[1] = s_g_cu[col + 1]
g_cu_cols = g_cu_cols.load().reshape((2, 1))
# apply gamma and causal mask
Gamma = cute.math.exp(g_cu_rows - g_cu_cols, fastmath=True)
tmp = qk[None, None, i] * Gamma
tmp = cute.where(row_indices >= col_indices + i * 8, tmp, 0.0)
# CuteDSL can't emit cvt.bf16x2.f32 here
attn_lo = cute.make_rmem_tensor(2, Uint32)
attn_lo[0] = cvt.fp32x2_to_bf16x2(tmp[0, 0], tmp[1, 0])
attn_lo[1] = cvt.fp32x2_to_bf16x2(tmp[0, 1], tmp[1, 1])
_tcgen05.st(warp_id_ * 32, p_tmem + i * 4, "16x128b", 1, attn_lo)
_tcgen05.wait_st()
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(mask_mbar)
parity ^= 1
else:
# epilogue warps
# for ldmatrix layout later
row0 = warp_id * 16 + lane_id // 4
row1 = row0 + 8
stage_id = 0
mma_parity = 0
op = cute.nvgpu.CopyUniversalOp()
cp_4B = cute.make_copy_atom(op, BFloat16, num_bits_per_copy=32)
stsm_op = warp.StMatrix8x8x16bOp(num_matrices=4, transpose=False)
stsm_atom = cute.make_copy_atom(stsm_op, BFloat16)
# ldmatrix layout
# [total_seq_len, ((2, 4, WIDTH/8), V_DIM/WIDTH)]
WIDTH = 64
o_view = cute.logical_divide(
o[None, v_head_id, None],
(None, cute.make_layout((2, 4, WIDTH // 8))),
)
# select lane: [total_seq_len, 2, WIDTH/8, V_DIM/WIDTH]
o_view = o_view[None, ((None, lane_id % 4, None), None)]
for global_chunk_id in range(bid, num_global_chunks, grid_x):
seq_id = chunk_indices[global_chunk_id, 0]
chunk_id = chunk_indices[global_chunk_id, 1]
bos = cu_seqlens[seq_id]
eos = cu_seqlens[seq_id + 1]
chunk_start = bos + chunk_id * BT
full_chunk = chunk_start + BT <= eos
g_cu_rows = cute.make_rmem_tensor(2, Float32)
g_cu_rows.fill(0.0)
# load g_cu
if chunk_start + row0 < eos:
g_cu_rows[0] = cute.math.exp(
g_cu[chunk_start + row0, v_head_id], fastmath=True
)
if chunk_start + row1 < eos:
g_cu_rows[1] = cute.math.exp(
g_cu[chunk_start + row1, v_head_id], fastmath=True
)
g_cu_rows = g_cu_rows.load().reshape((1, 2, 1))
if warp_id == 0:
cute.arch.mbarrier_wait(pv_mma_mbar + stage_id, mma_parity)
elif warp_id == 3 and full_chunk:
cute.arch.cp_async_bulk_wait_group(0, read=True)
cute.arch.barrier(barrier_id=2, number_of_threads=128)
_tcgen05.fence_after_thread_sync()
if full_chunk:
# use TMA store: tmem->rmem->smem->gmem
for i in cutlass.range_constexpr(V_dim // WIDTH):
qh = _tcgen05.ld(
warp_id * 32, qh_tmem + i * WIDTH, "16x256b", WIDTH // 8
)
pv = _tcgen05.ld(
warp_id * 32, out_tmem + i * WIDTH, "16x256b", WIDTH // 8
)
_tcgen05.wait_ld()
if i == V_dim // WIDTH - 1:
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(epi_mbar)
qh = qh.reshape((2, 2, WIDTH // 8))
pv = pv.reshape((2, 2, WIDTH // 8))
out_f32 = scale * (g_cu_rows * qh + pv)
out_bf16 = cute.make_rmem_tensor((8, WIDTH // 16), BFloat16)
out_bf16.store(out_f32.to(BFloat16).reshape((8, WIDTH // 16)))
# TODO: issue single cute.copy()
for j in cutlass.range_constexpr(WIDTH // 16):
s_row = warp_id * 16 + lane_id % 16
s_col = i * (WIDTH // 8) + j * 2 + lane_id // 16
sO_tile = cute.local_tile(sO[s_row, None], (8,), (s_col,))
cute.copy(stsm_atom, out_bf16[None, j], sO_tile)
cute.arch.barrier(barrier_id=2, number_of_threads=128)
fence_before_tma_store()
if warp_id == 3:
gO = cute.local_tile(
cute.domain_offset((bos, 0), tmaO[None, v_head_id, None]),
tiler=(BT, V_dim),
coord=(chunk_id, 0),
)
simple_tma_copy(O_tma_atom, sO, gO)
with cute.arch.elect_one():
cute.arch.cp_async_bulk_commit_group()
else:
# direct gmem store
# TODO: explore doing multiple 1D TMAs
for i in cutlass.range_constexpr(V_dim // WIDTH):
qh = _tcgen05.ld(
warp_id * 32, qh_tmem + i * WIDTH, "16x256b", WIDTH // 8
)
pv = _tcgen05.ld(
warp_id * 32, out_tmem + i * WIDTH, "16x256b", WIDTH // 8
)
_tcgen05.wait_ld()
if i == V_dim // WIDTH - 1:
_tcgen05.fence_before_thread_sync()
cute.arch.mbarrier_arrive(epi_mbar)
qh = qh.reshape((2, 2, WIDTH // 8))
pv = pv.reshape((2, 2, WIDTH // 8))
out_f32 = scale * (g_cu_rows * qh + pv)
out_bf16 = cute.make_rmem_tensor((2, 2, WIDTH // 8), BFloat16)
out_bf16.store(out_f32.to(BFloat16))
if chunk_start + row0 < eos:
cute.copy(
cp_4B,
out_bf16[None, 0, None],
o_view[chunk_start + row0, None, None, i],
)
if chunk_start + row1 < eos:
cute.copy(
cp_4B,
out_bf16[None, 1, None],
o_view[chunk_start + row1, None, None, i],
)
stage_id = (stage_id + 1) % num_stages
if stage_id == 0:
mma_parity ^= 1
@cache
@staticmethod
def compile(
H: int,
Hv: int,
K_dim: int,
V_dim: int,
BT: int = 64,
num_stages: int = 2,
):
total_t = cute.sym_int()
pad_t = cute.sym_int()
total_chunks_n = cute.sym_int()
h_outer_n = cute.sym_int()
cu_entries = cute.sym_int()
q = make_fake_tensor(BFloat16, (total_t, H, K_dim), divisibility=16)
k = make_fake_tensor(BFloat16, (total_t, H, K_dim), divisibility=16)
v_new = make_fake_tensor(BFloat16, (pad_t, Hv, V_dim), divisibility=16)
h_flat = make_fake_tensor(BFloat16, (h_outer_n, V_dim, K_dim), divisibility=16)
g_cu = make_fake_tensor(Float32, (total_t, Hv), divisibility=4)
o = make_fake_tensor(BFloat16, (total_t, Hv, V_dim), divisibility=16)
cu_seqlens = make_fake_tensor(Int32, (cu_entries,), divisibility=1)
chunk_indices = make_fake_tensor(Int32, (total_chunks_n, 2), divisibility=2)
total_chunks = make_fake_tensor(Int32, (1,), divisibility=1)
kernel = Sm100ChunkOKernel(
H,
Hv,
K_dim,
V_dim,
BT,
num_stages,
)
stream = cute.runtime.make_fake_stream(use_tvm_ffi_env_stream=True)
return cute.compile(
kernel,
q,
k,
v_new,
h_flat,
g_cu,
o,
cu_seqlens,
chunk_indices,
total_chunks,
Float32(1.0),
Int32(148),
stream,
options="--enable-tvm-ffi",
)
def o_cutedsl(
q: torch.Tensor,
k: torch.Tensor,
v_new_chunks: torch.Tensor,
h: torch.Tensor,
g_cu: torch.Tensor,
o: torch.Tensor,
cu_seqlens: torch.Tensor,
chunk_indices: torch.Tensor,
total_chunks: torch.Tensor,
scale: float,
num_sms: int = 148,
) -> None:
_, H, K_dim = q.shape
_, Hv, V_dim = o.shape
Sm100ChunkOKernel.compile(H, Hv, K_dim, V_dim)(
q,
k,
v_new_chunks.view(-1, Hv, V_dim),
h.view(-1, V_dim, K_dim),
g_cu,
o,
cu_seqlens,
chunk_indices,
total_chunks,
float(scale),
num_sms,
)
@@ -1,3 +1,15 @@
"""CuTe DSL kernels for GDN (Gated Delta Network) linear attention.
Decode path uses the existing ``cutedsl_fused_sigmoid_gating_delta_rule_update``
(works on SM90+).
Prefill (extend) path uses the ported vLLM SM100 chunkwise kernel
(``chunk_gated_delta_rule_cutedsl``). Requires SM100+ and ``head_k_dim == 128``.
"""
import logging
from typing import Optional
import torch
from sglang.jit_kernel.cutedsl_gdn import cutedsl_fused_sigmoid_gating_delta_rule_update
@@ -5,9 +17,64 @@ from sglang.srt.layers.attention.linear.kernels.kernel_backend import (
LinearAttnKernelBase,
)
logger = logging.getLogger(__name__)
def _is_blackwell() -> bool:
"""True iff running on SM100+ (Blackwell) where the ported kernel is valid."""
if not torch.cuda.is_available():
return False
major, _ = torch.cuda.get_device_capability()
return major >= 10
class CuteDSLGDNKernel(LinearAttnKernelBase):
"""CuTe DSL kernel for GDN decode (CUDA only)."""
"""CuTe DSL kernel for GDN.
Decode: ``cutedsl_fused_sigmoid_gating_delta_rule_update`` (SM90+).
Extend (prefill): chunkwise ``chunk_gated_delta_rule_cutedsl``
(SM100+ only, ``head_k_dim`` must be 128). On SM90 the prefill path is
unsupported; callers should query :attr:`supports_prefill` and fall back
to another backend (e.g. Triton).
"""
def __init__(self):
# The Blackwell extend kernel uses tcgen05/TMA-bulk-swizzle features
# that don't exist on SM90. The decode kernel does work on SM90+.
self.supports_prefill = _is_blackwell()
# Heavy CuteDSL imports are deferred to extend() so SM90 boxes can
# still construct the kernel just for decode.
self._extend_fn: Optional[callable] = None
self._prepare_meta_fn: Optional[callable] = None
self._l2norm_fn: Optional[callable] = None
def _ensure_extend_loaded(self, head_k_dim: int) -> None:
if self._extend_fn is not None:
return
if not self.supports_prefill:
major = (
torch.cuda.get_device_capability()[0]
if torch.cuda.is_available()
else -1
)
raise RuntimeError(
f"CuTe DSL GDN prefill requires SM100+ (Blackwell); got SM{major}."
)
if head_k_dim != 128:
raise RuntimeError(
f"CuTe DSL GDN prefill requires head_k_dim=128, got {head_k_dim}."
)
from sglang.srt.layers.attention.fla.l2norm import l2norm_fwd
from sglang.srt.layers.attention.linear.kernels.gdn_blackwell import (
chunk_gated_delta_rule_cutedsl,
prepare_metadata_cutedsl,
)
self._extend_fn = chunk_gated_delta_rule_cutedsl
self._prepare_meta_fn = prepare_metadata_cutedsl
self._l2norm_fn = l2norm_fwd
logger.info("Using CuTe DSL GDN prefill (Blackwell)")
def decode(
self,
@@ -40,8 +107,69 @@ class CuteDSLGDNKernel(LinearAttnKernelBase):
softplus_threshold=20.0,
)
def extend(self, *args, **kwargs):
raise NotImplementedError("CuteDSLGDNKernel only supports decode")
def extend(
self,
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor,
*,
ssm_states: torch.Tensor,
cache_indices: torch.Tensor,
query_start_loc: torch.Tensor,
**kwargs,
) -> tuple:
head_k_dim = k.shape[-1]
self._ensure_extend_loaded(head_k_dim)
total_seq_len = q.shape[1]
num_v_heads = v.shape[2]
head_v_dim = v.shape[3]
# L2 norm Q/K outside the kernel (same as flashinfer path).
q_norm = self._l2norm_fn(q[0].contiguous()).unsqueeze(0)
k_norm = self._l2norm_fn(k[0].contiguous()).unsqueeze(0)
v_in = v[0].contiguous().unsqueeze(0)
# Kernel expects log-space float32 gate per (token, v-head).
g_in = g[0].to(torch.float32).unsqueeze(0)
beta_in = beta[0].to(torch.float32).unsqueeze(0)
cu_seqlens = query_start_loc.to(torch.int32)
# Pool gather: remap padding (-1) to the last (sentinel) slot.
ssm_cache_indices = torch.where(
cache_indices >= 0,
cache_indices,
ssm_states.shape[0] - 1,
).to(torch.long)
initial_state = ssm_states[ssm_cache_indices].contiguous()
chunk_indices, chunk_offsets = self._prepare_meta_fn(
cu_seqlens, total_seq_len, chunk_size=64
)
output, final_state = self._extend_fn(
q=q_norm,
k=k_norm,
v=v_in,
g=g_in,
beta=beta_in,
initial_state=initial_state,
cu_seqlens=cu_seqlens,
chunk_indices=chunk_indices,
chunk_offsets=chunk_offsets,
)
ssm_states.index_copy_(
0,
ssm_cache_indices,
final_state.to(ssm_states.dtype),
)
# Match Triton extend interface: (output, last_recurrent_state, h).
# We've already written state back, so no need to return it.
return output, None, None
def target_verify(self, *args, **kwargs):
raise NotImplementedError("CuteDSLGDNKernel only supports decode")
raise NotImplementedError("CuteDSLGDNKernel does not support target_verify")