submission 118226
dxyz · python · License unknown
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submission_v2.py
curl "https://kernelindex.com/api/v1/implementations/kernelbot-nvfp4-gemm-118226?include=source"interfacepython
Compatibility
measured onNVIDIA B200
declared hardwareNVIDIA B200
architecturessm_100
dtypesfp8_e4m3, nvfp4
Benchmark evidence
1 measurement across 1 GPU, fastest first.
Operation / workload
Hardware
Latency
Rank
Observed
Reported · How evidence levels are derived →
Source and license
sourceavailable
revision digestsha256:4b6443fe2b000da927fde1da2ec2dbb5909be32a569742a7a72dcd25cfcaa405
license declaredunknown
license concludedunknown
authorsdxyz
imported2026-08-26
Techniques
Extracted from the mirrored source by pattern, never inferred. Each row cites its line.
fp4
Generate input tensors for NVFP4 block-scaled GEMM.fused-epilogue
- Computing epilogue subtilembarrier
self.epilog_sync_barrier = pipeline.NamedBarrier(persistent-kernel
tile_sched_params: utils.PersistentTileSchedulerParams,shared-memory
self.smem_capacity = utils.get_smem_capacity_in_bytes("sm_100")tcgen05
tcgen05.CtaGroup.TWO if self.use_2cta_instrs else tcgen05.CtaGroup.ONEwarp-specialization
ab_pipeline_producer_group = pipeline.CooperativeGroup(pipeline.Agent.Thread)Kernel source
submission_v2.py2322 lines
from torch._higher_order_ops.torchbind import call_torchbind_fake
import cuda.bindings.driver as cuda
import torch
from task import input_t, output_t
import cutlass
import cutlass.cute as cute
import cutlass.utils as utils
import cutlass.pipeline as pipeline
from cutlass.cute.nvgpu import cpasync, tcgen05
import cutlass.torch as cutlass_torch
import cutlass.utils.blackwell_helpers as sm100_utils
import cutlass.utils.blockscaled_layout as blockscaled_utils
from cutlass.cute.runtime import make_ptr
# Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: BSD-3-Clause
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# 1. Redistributions of source code must retain the above copyright notice, this
# list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
# 3. Neither the name of the copyright holder nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
import argparse
from typing import Type, Tuple, Union
import cuda.bindings.driver as cuda
import torch
import cutlass
import cutlass.cute as cute
from cutlass.cute.nvgpu import cpasync, tcgen05
import cutlass.torch as cutlass_torch
import cutlass.utils as utils
import cutlass.pipeline as pipeline
from cutlass.pipeline import pipeline_init_arrive, pipeline_init_wait
import cutlass.utils.blackwell_helpers as sm100_utils
import cutlass.utils.blockscaled_layout as blockscaled_utils
from cutlass.cute.runtime import from_dlpack
class Sm100BlockScaledPersistentDenseGemmKernel:
def __init__(
self,
sf_vec_size: int,
mma_tiler_mn: Tuple[int, int],
cluster_shape_mn: Tuple[int, int],
):
"""Initializes the configuration for a Blackwell dense GEMM kernel.
This configuration includes several key aspects:
1. MMA Instruction Settings (tcgen05):
- acc_dtype: Data types for MMA accumulator, always set to Float32
- sf_vec_size: Scalefactor A/B vector size.
- mma_tiler_mn: The (M, N) shape of the MMA instruction tiler.
2. Cluster Shape:
- cluster_shape_mn: The (ClusterM, ClusterN) shape of the CTA cluster.
:param sf_vec_size: Scalefactor vector size.
:type sf_vec_size: int
:param mma_tiler_mn: Tuple (M, N) shape of the MMA instruction.
:type mma_tiler_mn: Tuple[int, int]
:param cluster_shape_mn: Tuple (ClusterM, ClusterN) shape of the cluster.
:type cluster_shape_mn: Tuple[int, int]
"""
self.acc_dtype = cutlass.Float32
self.sf_vec_size = sf_vec_size
self.use_2cta_instrs = mma_tiler_mn[0] == 256
self.cluster_shape_mn = cluster_shape_mn
# K dimension is deferred in _setup_attributes
self.mma_tiler = (*mma_tiler_mn, 1)
self.cta_group = (
tcgen05.CtaGroup.TWO if self.use_2cta_instrs else tcgen05.CtaGroup.ONE
)
self.occupancy = 1
# Set specialized warp ids
self.epilog_warp_id = (
0,
1,
2,
3,
)
self.mma_warp_id = 4
self.tma_warp_id = 5
self.threads_per_cta = 32 * len(
(self.mma_warp_id, self.tma_warp_id, *self.epilog_warp_id)
)
# Set barrier id for epilogue sync and tmem ptr sync
self.epilog_sync_barrier = pipeline.NamedBarrier(
barrier_id=1,
num_threads=32 * len(self.epilog_warp_id),
)
self.tmem_alloc_barrier = pipeline.NamedBarrier(
barrier_id=2,
num_threads=32 * len((self.mma_warp_id, *self.epilog_warp_id)),
)
self.smem_capacity = utils.get_smem_capacity_in_bytes("sm_100")
SM100_TMEM_CAPACITY_COLUMNS = 512
self.num_tmem_alloc_cols = SM100_TMEM_CAPACITY_COLUMNS
def _setup_attributes(self):
"""Set up configurations that are dependent on GEMM inputs
This method configures various attributes based on the input tensor properties
(data types, leading dimensions) and kernel settings:
- Configuring tiled MMA
- Computing MMA/cluster/tile shapes
- Computing cluster layout
- Computing multicast CTAs for A/B/SFA/SFB
- Computing epilogue subtile
- Setting up A/B/SFA/SFB/C stage counts in shared memory
- Computing A/B/SFA/SFB/C shared memory layout
"""
# Compute mma instruction shapes
# (MMA_Tile_Shape_M, MMA_Tile_Shape_N, MMA_Inst_Shape_K)
self.mma_inst_shape_mn = (
self.mma_tiler[0],
self.mma_tiler[1],
)
# (CTA_Tile_Shape_M, Round_Up(MMA_Tile_Shape_N, 128), MMA_Inst_Shape_K)
self.mma_inst_shape_mn_sfb = (
self.mma_inst_shape_mn[0] // (2 if self.use_2cta_instrs else 1),
cute.round_up(self.mma_inst_shape_mn[1], 128),
)
tiled_mma = sm100_utils.make_blockscaled_trivial_tiled_mma(
self.a_dtype,
self.a_major_mode,
self.b_major_mode,
self.sf_dtype,
self.sf_vec_size,
self.cta_group,
self.mma_inst_shape_mn,
)
tiled_mma_sfb = sm100_utils.make_blockscaled_trivial_tiled_mma(
self.a_dtype,
self.a_major_mode,
self.b_major_mode,
self.sf_dtype,
self.sf_vec_size,
cute.nvgpu.tcgen05.CtaGroup.ONE,
self.mma_inst_shape_mn_sfb,
)
# Compute mma/cluster/tile shapes
mma_inst_shape_k = cute.size(tiled_mma.shape_mnk, mode=[2])
mma_inst_tile_k = 4
self.mma_tiler = (
self.mma_inst_shape_mn[0],
self.mma_inst_shape_mn[1],
mma_inst_shape_k * mma_inst_tile_k,
)
self.mma_tiler_sfb = (
self.mma_inst_shape_mn_sfb[0],
self.mma_inst_shape_mn_sfb[1],
mma_inst_shape_k * mma_inst_tile_k,
)
self.cta_tile_shape_mnk = (
self.mma_tiler[0] // cute.size(tiled_mma.thr_id.shape),
self.mma_tiler[1],
self.mma_tiler[2],
)
self.cta_tile_shape_mnk_sfb = (
self.mma_tiler_sfb[0] // cute.size(tiled_mma.thr_id.shape),
self.mma_tiler_sfb[1],
self.mma_tiler_sfb[2],
)
# Compute cluster layout
self.cluster_layout_vmnk = cute.tiled_divide(
cute.make_layout((*self.cluster_shape_mn, 1)),
(tiled_mma.thr_id.shape,),
)
self.cluster_layout_sfb_vmnk = cute.tiled_divide(
cute.make_layout((*self.cluster_shape_mn, 1)),
(tiled_mma_sfb.thr_id.shape,),
)
# Compute number of multicast CTAs for A/B
self.num_mcast_ctas_a = cute.size(self.cluster_layout_vmnk.shape[2])
self.num_mcast_ctas_b = cute.size(self.cluster_layout_vmnk.shape[1])
self.num_mcast_ctas_sfb = cute.size(self.cluster_layout_sfb_vmnk.shape[1])
self.is_a_mcast = self.num_mcast_ctas_a > 1
self.is_b_mcast = self.num_mcast_ctas_b > 1
self.is_sfb_mcast = self.num_mcast_ctas_sfb > 1
# Compute epilogue subtile
self.epi_tile = sm100_utils.compute_epilogue_tile_shape(
self.cta_tile_shape_mnk,
self.use_2cta_instrs,
self.c_layout,
self.c_dtype,
)
self.epi_tile_n = cute.size(self.epi_tile[1])
# Setup A/B/C stage count in shared memory and ACC stage count in tensor memory
self.num_acc_stage, self.num_ab_stage, self.num_c_stage = self._compute_stages(
tiled_mma,
self.mma_tiler,
self.a_dtype,
self.b_dtype,
self.epi_tile,
self.c_dtype,
self.c_layout,
self.sf_dtype,
self.sf_vec_size,
self.smem_capacity,
self.occupancy,
)
# Compute A/B/SFA/SFB/C shared memory layout
self.a_smem_layout_staged = sm100_utils.make_smem_layout_a(
tiled_mma,
self.mma_tiler,
self.a_dtype,
self.num_ab_stage,
)
self.b_smem_layout_staged = sm100_utils.make_smem_layout_b(
tiled_mma,
self.mma_tiler,
self.b_dtype,
self.num_ab_stage,
)
self.sfa_smem_layout_staged = blockscaled_utils.make_smem_layout_sfa(
tiled_mma,
self.mma_tiler,
self.sf_vec_size,
self.num_ab_stage,
)
self.sfb_smem_layout_staged = blockscaled_utils.make_smem_layout_sfb(
tiled_mma,
self.mma_tiler,
self.sf_vec_size,
self.num_ab_stage,
)
self.c_smem_layout_staged = sm100_utils.make_smem_layout_epi(
self.c_dtype,
self.c_layout,
self.epi_tile,
self.num_c_stage,
)
# Overlap and double buffer accumulator when num_acc_stage == 1 for cta_tile_n = 256 case
self.overlapping_accum = self.num_acc_stage == 1
# Compute number of TMEM columns for SFA/SFB/Accumulator
sf_atom_mn = 32
self.num_sfa_tmem_cols = (self.cta_tile_shape_mnk[0] // sf_atom_mn) * mma_inst_tile_k
self.num_sfb_tmem_cols = (self.cta_tile_shape_mnk_sfb[1] // sf_atom_mn) * mma_inst_tile_k
self.num_sf_tmem_cols = self.num_sfa_tmem_cols + self.num_sfb_tmem_cols
self.num_accumulator_tmem_cols = self.cta_tile_shape_mnk[1] * self.num_acc_stage if not self.overlapping_accum else self.cta_tile_shape_mnk[1] * 2 - self.num_sf_tmem_cols
# Only when overlapping_accum is enabled, we need to release accumulator buffer early in epilogue
self.iter_acc_early_release_in_epilogue = self.num_sf_tmem_cols // self.epi_tile_n
@cute.jit
def __call__(
self,
a_tensor_ptr: cute.Pointer,
b_tensor_ptr: cute.Pointer,
sfa_tensor_ptr: cute.Pointer,
sfb_tensor_ptr: cute.Pointer,
c_tensor_ptr: cute.Pointer,
problem_size: tuple,
max_active_clusters: cutlass.Constexpr,
epilogue_op: cutlass.Constexpr = lambda x: x,
):
"""Execute the GEMM operation in steps:
- Setup static attributes before smem/grid/tma computation
- Setup TMA load/store atoms and tensors
- Compute grid size with regard to hardware constraints
- Define shared storage for kernel
- Launch the kernel synchronously
:param a_tensor: Input tensor A
:type a_tensor: cute.Tensor
:param b_tensor: Input tensor B
:type b_tensor: cute.Tensor
:param sfa_tensor: Scale factor tensor A
:type sfa_tensor: cute.Tensor
:param sfb_tensor: Scale factor tensor B
:type sfb_tensor: cute.Tensor
:param c_tensor: Output tensor C
:type c_tensor: cute.Tensor
:param max_active_clusters: Maximum number of active clusters
:type max_active_clusters: cutlass.Constexpr
:param epilogue_op: Optional elementwise lambda function to apply to the output tensor
:type epilogue_op: cutlass.Constexpr
:raises TypeError: If input data types are incompatible with the MMA instruction.
"""
m, n, k, l = problem_size
# Setup attributes that depend on gemm inputs
a_tensor = cute.make_tensor(
a_tensor_ptr,
cute.make_layout(
(m, cute.assume(k, 32), l),
stride=(cute.assume(k, 32), 1, cute.assume(m * k, 32)),
),
)
b_tensor = cute.make_tensor(
b_tensor_ptr,
cute.make_layout(
(n, cute.assume(k, 32), l),
stride=(cute.assume(k, 32), 1, cute.assume(n * k, 32)),
),
)
c_tensor = cute.make_tensor(
c_tensor_ptr, cute.make_layout((cute.assume(m, 32), n, l), stride=(n, 1, m * n))
)
# Setup sfa/sfb tensor by filling A/B tensor to scale factor atom layout
# ((Atom_M, Rest_M),(Atom_K, Rest_K),RestL)
sfa_layout = blockscaled_utils.tile_atom_to_shape_SF(
a_tensor.shape, self.sf_vec_size
)
sfa_tensor = cute.make_tensor(sfa_tensor_ptr, sfa_layout)
# ((Atom_N, Rest_N),(Atom_K, Rest_K),RestL)
sfb_layout = blockscaled_utils.tile_atom_to_shape_SF(
b_tensor.shape, self.sf_vec_size
)
sfb_tensor = cute.make_tensor(sfb_tensor_ptr, sfb_layout)
# Setup static attributes before smem/grid/tma computation
self.a_dtype: Type[cutlass.Numeric] = a_tensor.element_type
self.b_dtype: Type[cutlass.Numeric] = b_tensor.element_type
self.sf_dtype: Type[cutlass.Numeric] = sfa_tensor.element_type
self.c_dtype: Type[cutlass.Numeric] = c_tensor.element_type
self.a_major_mode = utils.LayoutEnum.from_tensor(a_tensor).mma_major_mode()
self.b_major_mode = utils.LayoutEnum.from_tensor(b_tensor).mma_major_mode()
self.c_layout = utils.LayoutEnum.from_tensor(c_tensor)
# Check if input data types are compatible with MMA instruction
if cutlass.const_expr(self.a_dtype != self.b_dtype):
raise TypeError(f"Type must match: {self.a_dtype} != {self.b_dtype}")
# Setup attributes that dependent on gemm inputs
self._setup_attributes()
# Setup sfa/sfb tensor by filling A/B tensor to scale factor atom layout
# ((Atom_M, Rest_M),(Atom_K, Rest_K),RestL)
sfa_layout = blockscaled_utils.tile_atom_to_shape_SF(
a_tensor.shape, self.sf_vec_size
)
sfa_tensor = cute.make_tensor(sfa_tensor.iterator, sfa_layout)
# ((Atom_N, Rest_N),(Atom_K, Rest_K),RestL)
sfb_layout = blockscaled_utils.tile_atom_to_shape_SF(
b_tensor.shape, self.sf_vec_size
)
sfb_tensor = cute.make_tensor(sfb_tensor.iterator, sfb_layout)
tiled_mma = sm100_utils.make_blockscaled_trivial_tiled_mma(
self.a_dtype,
self.a_major_mode,
self.b_major_mode,
self.sf_dtype,
self.sf_vec_size,
self.cta_group,
self.mma_inst_shape_mn,
)
tiled_mma_sfb = sm100_utils.make_blockscaled_trivial_tiled_mma(
self.a_dtype,
self.a_major_mode,
self.b_major_mode,
self.sf_dtype,
self.sf_vec_size,
cute.nvgpu.tcgen05.CtaGroup.ONE,
self.mma_inst_shape_mn_sfb,
)
atom_thr_size = cute.size(tiled_mma.thr_id.shape)
# Setup TMA load for A
a_op = sm100_utils.cluster_shape_to_tma_atom_A(
self.cluster_shape_mn, tiled_mma.thr_id
)
a_smem_layout = cute.slice_(self.a_smem_layout_staged, (None, None, None, 0))
tma_atom_a, tma_tensor_a = cute.nvgpu.make_tiled_tma_atom_A(
a_op,
a_tensor,
a_smem_layout,
self.mma_tiler,
tiled_mma,
self.cluster_layout_vmnk.shape,
)
# Setup TMA load for B
b_op = sm100_utils.cluster_shape_to_tma_atom_B(
self.cluster_shape_mn, tiled_mma.thr_id
)
b_smem_layout = cute.slice_(self.b_smem_layout_staged, (None, None, None, 0))
tma_atom_b, tma_tensor_b = cute.nvgpu.make_tiled_tma_atom_B(
b_op,
b_tensor,
b_smem_layout,
self.mma_tiler,
tiled_mma,
self.cluster_layout_vmnk.shape,
)
# Setup TMA load for SFA
sfa_op = sm100_utils.cluster_shape_to_tma_atom_A(
self.cluster_shape_mn, tiled_mma.thr_id
)
sfa_smem_layout = cute.slice_(
self.sfa_smem_layout_staged, (None, None, None, 0)
)
tma_atom_sfa, tma_tensor_sfa = cute.nvgpu.make_tiled_tma_atom_A(
sfa_op,
sfa_tensor,
sfa_smem_layout,
self.mma_tiler,
tiled_mma,
self.cluster_layout_vmnk.shape,
internal_type=cutlass.Int16,
)
# Setup TMA load for SFB
sfb_op = sm100_utils.cluster_shape_to_tma_atom_SFB(
self.cluster_shape_mn, tiled_mma.thr_id
)
sfb_smem_layout = cute.slice_(
self.sfb_smem_layout_staged, (None, None, None, 0)
)
tma_atom_sfb, tma_tensor_sfb = cute.nvgpu.make_tiled_tma_atom_B(
sfb_op,
sfb_tensor,
sfb_smem_layout,
self.mma_tiler_sfb,
tiled_mma_sfb,
self.cluster_layout_sfb_vmnk.shape,
internal_type=cutlass.Int16,
)
if cutlass.const_expr(self.cta_tile_shape_mnk[1] == 192):
x = tma_tensor_sfb.stride[0][1]
y = cute.ceil_div(tma_tensor_sfb.shape[0][1], 4)
new_shape = (
(
tma_tensor_sfb.shape[0][0],
((2, 2), y)
),
tma_tensor_sfb.shape[1],
tma_tensor_sfb.shape[2]
)
# Use right multiplication for ScaledBasis (3 * x instead of x * 3)
x_times_3 = 3 * x
new_stride = (
(
tma_tensor_sfb.stride[0][0],
((x, x), x_times_3)
),
tma_tensor_sfb.stride[1],
tma_tensor_sfb.stride[2]
)
tma_tensor_sfb_new_layout = cute.make_layout(new_shape, stride=new_stride)
tma_tensor_sfb = cute.make_tensor(tma_tensor_sfb.iterator, tma_tensor_sfb_new_layout)
a_copy_size = cute.size_in_bytes(self.a_dtype, a_smem_layout)
b_copy_size = cute.size_in_bytes(self.b_dtype, b_smem_layout)
sfa_copy_size = cute.size_in_bytes(self.sf_dtype, sfa_smem_layout)
sfb_copy_size = cute.size_in_bytes(self.sf_dtype, sfb_smem_layout)
self.num_tma_load_bytes = (
a_copy_size + b_copy_size + sfa_copy_size + sfb_copy_size
) * atom_thr_size
# Setup TMA store for C
epi_smem_layout = cute.slice_(self.c_smem_layout_staged, (None, None, 0))
tma_atom_c, tma_tensor_c = cpasync.make_tiled_tma_atom(
cpasync.CopyBulkTensorTileS2GOp(),
c_tensor,
epi_smem_layout,
self.epi_tile,
)
# Compute grid size
self.tile_sched_params, grid = self._compute_grid(
c_tensor,
self.cta_tile_shape_mnk,
self.cluster_shape_mn,
max_active_clusters,
)
self.buffer_align_bytes = 1024
# Define shared storage for kernel
@cute.struct
class SharedStorage:
ab_full_mbar_ptr: cute.struct.MemRange[cutlass.Int64, self.num_ab_stage]
ab_empty_mbar_ptr: cute.struct.MemRange[cutlass.Int64, self.num_ab_stage]
acc_full_mbar_ptr: cute.struct.MemRange[cutlass.Int64, self.num_acc_stage]
acc_empty_mbar_ptr: cute.struct.MemRange[cutlass.Int64, self.num_acc_stage]
tmem_dealloc_mbar_ptr: cutlass.Int64
tmem_holding_buf: cutlass.Int32
# (EPI_TILE_M, EPI_TILE_N, STAGE)
sC: cute.struct.Align[
cute.struct.MemRange[
self.c_dtype,
cute.cosize(self.c_smem_layout_staged.outer),
],
self.buffer_align_bytes,
]
# (MMA, MMA_M, MMA_K, STAGE)
sA: cute.struct.Align[
cute.struct.MemRange[
self.a_dtype, cute.cosize(self.a_smem_layout_staged.outer)
],
self.buffer_align_bytes,
]
# (MMA, MMA_N, MMA_K, STAGE)
sB: cute.struct.Align[
cute.struct.MemRange[
self.b_dtype, cute.cosize(self.b_smem_layout_staged.outer)
],
self.buffer_align_bytes,
]
# (MMA, MMA_M, MMA_K, STAGE)
sSFA: cute.struct.Align[
cute.struct.MemRange[
self.sf_dtype, cute.cosize(self.sfa_smem_layout_staged)
],
self.buffer_align_bytes,
]
# (MMA, MMA_N, MMA_K, STAGE)
sSFB: cute.struct.Align[
cute.struct.MemRange[
self.sf_dtype, cute.cosize(self.sfb_smem_layout_staged)
],
self.buffer_align_bytes,
]
self.shared_storage = SharedStorage
# Launch the kernel synchronously
self.kernel(
tiled_mma,
tiled_mma_sfb,
tma_atom_a,
tma_tensor_a,
tma_atom_b,
tma_tensor_b,
tma_atom_sfa,
tma_tensor_sfa,
tma_atom_sfb,
tma_tensor_sfb,
tma_atom_c,
tma_tensor_c,
self.cluster_layout_vmnk,
self.cluster_layout_sfb_vmnk,
self.a_smem_layout_staged,
self.b_smem_layout_staged,
self.sfa_smem_layout_staged,
self.sfb_smem_layout_staged,
self.c_smem_layout_staged,
self.epi_tile,
self.tile_sched_params,
epilogue_op,
).launch(
grid=grid,
block=[self.threads_per_cta, 1, 1],
cluster=(*self.cluster_shape_mn, 1),
min_blocks_per_mp=1,
)
return
# GPU device kernel
@cute.kernel
def kernel(
self,
tiled_mma: cute.TiledMma,
tiled_mma_sfb: cute.TiledMma,
tma_atom_a: cute.CopyAtom,
mA_mkl: cute.Tensor,
tma_atom_b: cute.CopyAtom,
mB_nkl: cute.Tensor,
tma_atom_sfa: cute.CopyAtom,
mSFA_mkl: cute.Tensor,
tma_atom_sfb: cute.CopyAtom,
mSFB_nkl: cute.Tensor,
tma_atom_c: cute.CopyAtom,
mC_mnl: cute.Tensor,
cluster_layout_vmnk: cute.Layout,
cluster_layout_sfb_vmnk: cute.Layout,
a_smem_layout_staged: cute.ComposedLayout,
b_smem_layout_staged: cute.ComposedLayout,
sfa_smem_layout_staged: cute.Layout,
sfb_smem_layout_staged: cute.Layout,
c_smem_layout_staged: Union[cute.Layout, cute.ComposedLayout],
epi_tile: cute.Tile,
tile_sched_params: utils.PersistentTileSchedulerParams,
epilogue_op: cutlass.Constexpr,
):
"""
GPU device kernel performing the Persistent batched GEMM computation.
"""
warp_idx = cute.arch.warp_idx()
warp_idx = cute.arch.make_warp_uniform(warp_idx)
#
# Prefetch tma desc
#
if warp_idx == self.tma_warp_id:
cpasync.prefetch_descriptor(tma_atom_a)
cpasync.prefetch_descriptor(tma_atom_b)
cpasync.prefetch_descriptor(tma_atom_sfa)
cpasync.prefetch_descriptor(tma_atom_sfb)
cpasync.prefetch_descriptor(tma_atom_c)
use_2cta_instrs = cute.size(tiled_mma.thr_id.shape) == 2
#
# Setup cta/thread coordinates
#
# Coords inside cluster
bidx, bidy, bidz = cute.arch.block_idx()
mma_tile_coord_v = bidx % cute.size(tiled_mma.thr_id.shape)
is_leader_cta = mma_tile_coord_v == 0
cta_rank_in_cluster = cute.arch.make_warp_uniform(
cute.arch.block_idx_in_cluster()
)
block_in_cluster_coord_vmnk = cluster_layout_vmnk.get_flat_coord(
cta_rank_in_cluster
)
block_in_cluster_coord_sfb_vmnk = cluster_layout_sfb_vmnk.get_flat_coord(
cta_rank_in_cluster
)
# Coord inside cta
tidx, _, _ = cute.arch.thread_idx()
#
# Alloc and init: a+b full/empty, accumulator full/empty, tensor memory dealloc barrier
#
smem = utils.SmemAllocator()
storage = smem.allocate(self.shared_storage)
# Initialize mainloop ab_pipeline (barrier) and states
ab_pipeline_producer_group = pipeline.CooperativeGroup(pipeline.Agent.Thread)
num_tma_producer = self.num_mcast_ctas_a + self.num_mcast_ctas_b - 1
ab_pipeline_consumer_group = pipeline.CooperativeGroup(
pipeline.Agent.Thread, num_tma_producer
)
ab_pipeline = pipeline.PipelineTmaUmma.create(
barrier_storage=storage.ab_full_mbar_ptr.data_ptr(),
num_stages=self.num_ab_stage,
producer_group=ab_pipeline_producer_group,
consumer_group=ab_pipeline_consumer_group,
tx_count=self.num_tma_load_bytes,
cta_layout_vmnk=cluster_layout_vmnk,
defer_sync=True,
)
# Initialize acc_pipeline (barrier) and states
acc_pipeline_producer_group = pipeline.CooperativeGroup(pipeline.Agent.Thread)
num_acc_consumer_threads = len(self.epilog_warp_id) * (
2 if use_2cta_instrs else 1
)
acc_pipeline_consumer_group = pipeline.CooperativeGroup(
pipeline.Agent.Thread, num_acc_consumer_threads
)
acc_pipeline = pipeline.PipelineUmmaAsync.create(
barrier_storage=storage.acc_full_mbar_ptr.data_ptr(),
num_stages=self.num_acc_stage,
producer_group=acc_pipeline_producer_group,
consumer_group=acc_pipeline_consumer_group,
cta_layout_vmnk=cluster_layout_vmnk,
defer_sync=True,
)
# Tensor memory dealloc barrier init
tmem = utils.TmemAllocator(
storage.tmem_holding_buf,
barrier_for_retrieve=self.tmem_alloc_barrier,
allocator_warp_id=self.epilog_warp_id[0],
is_two_cta=use_2cta_instrs,
two_cta_tmem_dealloc_mbar_ptr=storage.tmem_dealloc_mbar_ptr,
)
# Cluster arrive after barrier init
pipeline_init_arrive(cluster_shape_mn=self.cluster_shape_mn, is_relaxed=True)
#
# Setup smem tensor A/B/SFA/SFB/C
#
# (EPI_TILE_M, EPI_TILE_N, STAGE)
sC = storage.sC.get_tensor(
c_smem_layout_staged.outer, swizzle=c_smem_layout_staged.inner
)
# (MMA, MMA_M, MMA_K, STAGE)
sA = storage.sA.get_tensor(
a_smem_layout_staged.outer, swizzle=a_smem_layout_staged.inner
)
# (MMA, MMA_N, MMA_K, STAGE)
sB = storage.sB.get_tensor(
b_smem_layout_staged.outer, swizzle=b_smem_layout_staged.inner
)
# (MMA, MMA_M, MMA_K, STAGE)
sSFA = storage.sSFA.get_tensor(sfa_smem_layout_staged)
# (MMA, MMA_N, MMA_K, STAGE)
sSFB = storage.sSFB.get_tensor(sfb_smem_layout_staged)
#
# Compute multicast mask for A/B/SFA/SFB buffer full
#
a_full_mcast_mask = None
b_full_mcast_mask = None
sfa_full_mcast_mask = None
sfb_full_mcast_mask = None
if cutlass.const_expr(self.is_a_mcast or self.is_b_mcast or use_2cta_instrs):
a_full_mcast_mask = cpasync.create_tma_multicast_mask(
cluster_layout_vmnk, block_in_cluster_coord_vmnk, mcast_mode=2
)
b_full_mcast_mask = cpasync.create_tma_multicast_mask(
cluster_layout_vmnk, block_in_cluster_coord_vmnk, mcast_mode=1
)
sfa_full_mcast_mask = cpasync.create_tma_multicast_mask(
cluster_layout_vmnk, block_in_cluster_coord_vmnk, mcast_mode=2
)
sfb_full_mcast_mask = cpasync.create_tma_multicast_mask(
cluster_layout_sfb_vmnk, block_in_cluster_coord_sfb_vmnk, mcast_mode=1
)
#
# Local_tile partition global tensors
#
# (bM, bK, RestM, RestK, RestL)
gA_mkl = cute.local_tile(
mA_mkl, cute.slice_(self.mma_tiler, (None, 0, None)), (None, None, None)
)
# (bN, bK, RestN, RestK, RestL)
gB_nkl = cute.local_tile(
mB_nkl, cute.slice_(self.mma_tiler, (0, None, None)), (None, None, None)
)
# (bM, bK, RestM, RestK, RestL)
gSFA_mkl = cute.local_tile(
mSFA_mkl, cute.slice_(self.mma_tiler, (None, 0, None)), (None, None, None)
)
# (bN, bK, RestN, RestK, RestL)
gSFB_nkl = cute.local_tile(
mSFB_nkl,
cute.slice_(self.mma_tiler_sfb, (0, None, None)),
(None, None, None),
)
# (bM, bN, RestM, RestN, RestL)
gC_mnl = cute.local_tile(
mC_mnl, cute.slice_(self.mma_tiler, (None, None, 0)), (None, None, None)
)
k_tile_cnt = cute.size(gA_mkl, mode=[3])
#
# Partition global tensor for TiledMMA_A/B/C
#
thr_mma = tiled_mma.get_slice(mma_tile_coord_v)
thr_mma_sfb = tiled_mma_sfb.get_slice(mma_tile_coord_v)
# (MMA, MMA_M, MMA_K, RestM, RestK, RestL)
tCgA = thr_mma.partition_A(gA_mkl)
# (MMA, MMA_N, MMA_K, RestN, RestK, RestL)
tCgB = thr_mma.partition_B(gB_nkl)
# (MMA, MMA_M, MMA_K, RestM, RestK, RestL)
tCgSFA = thr_mma.partition_A(gSFA_mkl)
# (MMA, MMA_N, MMA_K, RestN, RestK, RestL)
tCgSFB = thr_mma_sfb.partition_B(gSFB_nkl)
# (MMA, MMA_M, MMA_N, RestM, RestN, RestL)
tCgC = thr_mma.partition_C(gC_mnl)
#
# Partition global/shared tensor for TMA load A/B
#
# TMA load A partition_S/D
a_cta_layout = cute.make_layout(
cute.slice_(cluster_layout_vmnk, (0, 0, None, 0)).shape
)
# ((atom_v, rest_v), STAGE)
# ((atom_v, rest_v), RestM, RestK, RestL)
tAsA, tAgA = cpasync.tma_partition(
tma_atom_a,
block_in_cluster_coord_vmnk[2],
a_cta_layout,
cute.group_modes(sA, 0, 3),
cute.group_modes(tCgA, 0, 3),
)
# TMA load B partition_S/D
b_cta_layout = cute.make_layout(
cute.slice_(cluster_layout_vmnk, (0, None, 0, 0)).shape
)
# ((atom_v, rest_v), STAGE)
# ((atom_v, rest_v), RestN, RestK, RestL)
tBsB, tBgB = cpasync.tma_partition(
tma_atom_b,
block_in_cluster_coord_vmnk[1],
b_cta_layout,
cute.group_modes(sB, 0, 3),
cute.group_modes(tCgB, 0, 3),
)
# TMA load SFA partition_S/D
sfa_cta_layout = a_cta_layout
# ((atom_v, rest_v), STAGE)
# ((atom_v, rest_v), RestM, RestK, RestL)
tAsSFA, tAgSFA = cute.nvgpu.cpasync.tma_partition(
tma_atom_sfa,
block_in_cluster_coord_vmnk[2],
sfa_cta_layout,
cute.group_modes(sSFA, 0, 3),
cute.group_modes(tCgSFA, 0, 3),
)
tAsSFA = cute.filter_zeros(tAsSFA)
tAgSFA = cute.filter_zeros(tAgSFA)
# TMA load SFB partition_S/D
sfb_cta_layout = cute.make_layout(
cute.slice_(cluster_layout_sfb_vmnk, (0, None, 0, 0)).shape
)
# ((atom_v, rest_v), STAGE)
# ((atom_v, rest_v), RestN, RestK, RestL)
tBsSFB, tBgSFB = cute.nvgpu.cpasync.tma_partition(
tma_atom_sfb,
block_in_cluster_coord_sfb_vmnk[1],
sfb_cta_layout,
cute.group_modes(sSFB, 0, 3),
cute.group_modes(tCgSFB, 0, 3),
)
tBsSFB = cute.filter_zeros(tBsSFB)
tBgSFB = cute.filter_zeros(tBgSFB)
#
# Partition shared/tensor memory tensor for TiledMMA_A/B/C
#
# (MMA, MMA_M, MMA_K, STAGE)
tCrA = tiled_mma.make_fragment_A(sA)
# (MMA, MMA_N, MMA_K, STAGE)
tCrB = tiled_mma.make_fragment_B(sB)
# (MMA, MMA_M, MMA_N)
acc_shape = tiled_mma.partition_shape_C(self.mma_tiler[:2])
if cutlass.const_expr(self.overlapping_accum):
num_acc_stage_overlapped = 2
tCtAcc_fake = tiled_mma.make_fragment_C(
cute.append(acc_shape, num_acc_stage_overlapped)
)
# (MMA, MMA_M, MMA_N, STAGE)
tCtAcc_fake = cute.make_tensor(
tCtAcc_fake.iterator,
cute.make_layout(
tCtAcc_fake.shape,
stride = (
tCtAcc_fake.stride[0],
tCtAcc_fake.stride[1],
tCtAcc_fake.stride[2],
(256 - self.num_sf_tmem_cols) * tCtAcc_fake.stride[0][1]
)
)
)
else:
# (MMA, MMA_M, MMA_N, STAGE)
tCtAcc_fake = tiled_mma.make_fragment_C(
cute.append(acc_shape, self.num_acc_stage)
)
#
# Cluster wait before tensor memory alloc
#
pipeline_init_wait(cluster_shape_mn=self.cluster_shape_mn)
#
# Specialized TMA load warp
#
if warp_idx == self.tma_warp_id:
#
# Persistent tile scheduling loop
#
tile_sched = utils.StaticPersistentTileScheduler.create(
tile_sched_params, cute.arch.block_idx(), cute.arch.grid_dim()
)
work_tile = tile_sched.initial_work_tile_info()
ab_producer_state = pipeline.make_pipeline_state(
pipeline.PipelineUserType.Producer, self.num_ab_stage
)
while work_tile.is_valid_tile:
# Get tile coord from tile scheduler
cur_tile_coord = work_tile.tile_idx
mma_tile_coord_mnl = (
cur_tile_coord[0] // cute.size(tiled_mma.thr_id.shape),
cur_tile_coord[1],
cur_tile_coord[2],
)
#
# Slice to per mma tile index
#
# ((atom_v, rest_v), RestK)
tAgA_slice = tAgA[
(None, mma_tile_coord_mnl[0], None, mma_tile_coord_mnl[2])
]
# ((atom_v, rest_v), RestK)
tBgB_slice = tBgB[
(None, mma_tile_coord_mnl[1], None, mma_tile_coord_mnl[2])
]
# ((atom_v, rest_v), RestK)
tAgSFA_slice = tAgSFA[
(None, mma_tile_coord_mnl[0], None, mma_tile_coord_mnl[2])
]
slice_n = mma_tile_coord_mnl[1]
if cutlass.const_expr(self.cta_tile_shape_mnk[1] == 64):
slice_n = mma_tile_coord_mnl[1] // 2
# ((atom_v, rest_v), RestK)
tBgSFB_slice = tBgSFB[
(None, slice_n, None, mma_tile_coord_mnl[2])
]
# Peek (try_wait) AB buffer empty for k_tile = prefetch_k_tile_cnt
ab_producer_state.reset_count()
peek_ab_empty_status = cutlass.Boolean(1)
if ab_producer_state.count < k_tile_cnt:
peek_ab_empty_status = ab_pipeline.producer_try_acquire(
ab_producer_state
)
#
# Tma load loop
#
for k_tile in cutlass.range(0, k_tile_cnt, 1, unroll=1):
# Conditionally wait for AB buffer empty
ab_pipeline.producer_acquire(
ab_producer_state, peek_ab_empty_status
)
# TMA load A/B/SFA/SFB
cute.copy(
tma_atom_a,
tAgA_slice[(None, ab_producer_state.count)],
tAsA[(None, ab_producer_state.index)],
tma_bar_ptr=ab_pipeline.producer_get_barrier(ab_producer_state),
mcast_mask=a_full_mcast_mask,
)
cute.copy(
tma_atom_b,
tBgB_slice[(None, ab_producer_state.count)],
tBsB[(None, ab_producer_state.index)],
tma_bar_ptr=ab_pipeline.producer_get_barrier(ab_producer_state),
mcast_mask=b_full_mcast_mask,
)
cute.copy(
tma_atom_sfa,
tAgSFA_slice[(None, ab_producer_state.count)],
tAsSFA[(None, ab_producer_state.index)],
tma_bar_ptr=ab_pipeline.producer_get_barrier(ab_producer_state),
mcast_mask=sfa_full_mcast_mask,
)
cute.copy(
tma_atom_sfb,
tBgSFB_slice[(None, ab_producer_state.count)],
tBsSFB[(None, ab_producer_state.index)],
tma_bar_ptr=ab_pipeline.producer_get_barrier(ab_producer_state),
mcast_mask=sfb_full_mcast_mask,
)
# Peek (try_wait) AB buffer empty for k_tile = prefetch_k_tile_cnt + k_tile + 1
ab_producer_state.advance()
peek_ab_empty_status = cutlass.Boolean(1)
if ab_producer_state.count < k_tile_cnt:
peek_ab_empty_status = ab_pipeline.producer_try_acquire(
ab_producer_state
)
#
# Advance to next tile
#
tile_sched.advance_to_next_work()
work_tile = tile_sched.get_current_work()
#
# Wait A/B buffer empty
#
ab_pipeline.producer_tail(ab_producer_state)
#
# Specialized MMA warp
#
if warp_idx == self.mma_warp_id:
#
# Bar sync for retrieve tensor memory ptr from shared mem
#
tmem.wait_for_alloc()
#
# Retrieving tensor memory ptr and make accumulator/SFA/SFB tensor
#
acc_tmem_ptr = tmem.retrieve_ptr(self.acc_dtype)
# Make accumulator tmem tensor
# (MMA, MMA_M, MMA_N, STAGE)
tCtAcc_base = cute.make_tensor(acc_tmem_ptr, tCtAcc_fake.layout)
# Make SFA tmem tensor
sfa_tmem_ptr = cute.recast_ptr(
acc_tmem_ptr + self.num_accumulator_tmem_cols,
dtype=self.sf_dtype,
)
# (MMA, MMA_M, MMA_K)
tCtSFA_layout = blockscaled_utils.make_tmem_layout_sfa(
tiled_mma,
self.mma_tiler,
self.sf_vec_size,
cute.slice_(sfa_smem_layout_staged, (None, None, None, 0)),
)
tCtSFA = cute.make_tensor(sfa_tmem_ptr, tCtSFA_layout)
# Make SFB tmem tensor
sfb_tmem_ptr = cute.recast_ptr(
acc_tmem_ptr + self.num_accumulator_tmem_cols + self.num_sfa_tmem_cols,
dtype=self.sf_dtype,
)
# (MMA, MMA_N, MMA_K)
tCtSFB_layout = blockscaled_utils.make_tmem_layout_sfb(
tiled_mma,
self.mma_tiler,
self.sf_vec_size,
cute.slice_(sfb_smem_layout_staged, (None, None, None, 0)),
)
tCtSFB = cute.make_tensor(sfb_tmem_ptr, tCtSFB_layout)
#
# Partition for S2T copy of SFA/SFB
#
(
tiled_copy_s2t_sfa,
tCsSFA_compact_s2t,
tCtSFA_compact_s2t,
) = self.mainloop_s2t_copy_and_partition(sSFA, tCtSFA)
(
tiled_copy_s2t_sfb,
tCsSFB_compact_s2t,
tCtSFB_compact_s2t,
) = self.mainloop_s2t_copy_and_partition(sSFB, tCtSFB)
#
# Persistent tile scheduling loop
#
tile_sched = utils.StaticPersistentTileScheduler.create(
tile_sched_params, cute.arch.block_idx(), cute.arch.grid_dim()
)
work_tile = tile_sched.initial_work_tile_info()
ab_consumer_state = pipeline.make_pipeline_state(
pipeline.PipelineUserType.Consumer, self.num_ab_stage
)
acc_producer_state = pipeline.make_pipeline_state(
pipeline.PipelineUserType.Producer, self.num_acc_stage
)
while work_tile.is_valid_tile:
# Get tile coord from tile scheduler
cur_tile_coord = work_tile.tile_idx
mma_tile_coord_mnl = (
cur_tile_coord[0] // cute.size(tiled_mma.thr_id.shape),
cur_tile_coord[1],
cur_tile_coord[2],
)
# Get accumulator stage index
if cutlass.const_expr(self.overlapping_accum):
acc_stage_index = acc_producer_state.phase ^ 1
else:
acc_stage_index = acc_producer_state.index
# Set tensor memory buffer for current tile
# (MMA, MMA_M, MMA_N)
tCtAcc = tCtAcc_base[(None, None, None, acc_stage_index)]
# Peek (try_wait) AB buffer full for k_tile = 0
ab_consumer_state.reset_count()
peek_ab_full_status = cutlass.Boolean(1)
if ab_consumer_state.count < k_tile_cnt and is_leader_cta:
peek_ab_full_status = ab_pipeline.consumer_try_wait(
ab_consumer_state
)
#
# Wait for accumulator buffer empty
#
if is_leader_cta:
acc_pipeline.producer_acquire(acc_producer_state)
tCtSFB_mma = tCtSFB
if cutlass.const_expr(self.cta_tile_shape_mnk[1] == 192):
# If this is an ODD tile, shift the TMEM start address for cta_tile_shape_n=192 case by two words (ignores first 64 columns of SFB)
offset = cutlass.Int32(2) if mma_tile_coord_mnl[1] % 2 == 1 else cutlass.Int32(0)
shifted_ptr = cute.recast_ptr(
acc_tmem_ptr
+ self.num_accumulator_tmem_cols
+ self.num_sfa_tmem_cols
+ offset,
dtype=self.sf_dtype,
)
tCtSFB_mma = cute.make_tensor(shifted_ptr, tCtSFB_layout)
elif cutlass.const_expr(self.cta_tile_shape_mnk[1] == 64):
# Move in increments of 64 columns of SFB
offset = cutlass.Int32((mma_tile_coord_mnl[1] % 2) * 2)
shifted_ptr = cute.recast_ptr(
acc_tmem_ptr
+ self.num_accumulator_tmem_cols
+ self.num_sfa_tmem_cols
+ offset,
dtype=self.sf_dtype,
)
tCtSFB_mma = cute.make_tensor(shifted_ptr, tCtSFB_layout)
#
# Reset the ACCUMULATE field for each tile
#
tiled_mma.set(tcgen05.Field.ACCUMULATE, False)
#
# Mma mainloop
#
for k_tile in range(k_tile_cnt):
if is_leader_cta:
# Conditionally wait for AB buffer full
ab_pipeline.consumer_wait(
ab_consumer_state, peek_ab_full_status
)
# Copy SFA/SFB from smem to tmem
s2t_stage_coord = (
None,
None,
None,
None,
ab_consumer_state.index,
)
tCsSFA_compact_s2t_staged = tCsSFA_compact_s2t[s2t_stage_coord]
tCsSFB_compact_s2t_staged = tCsSFB_compact_s2t[s2t_stage_coord]
cute.copy(
tiled_copy_s2t_sfa,
tCsSFA_compact_s2t_staged,
tCtSFA_compact_s2t,
)
cute.copy(
tiled_copy_s2t_sfb,
tCsSFB_compact_s2t_staged,
tCtSFB_compact_s2t,
)
# tCtAcc += tCrA * tCrSFA * tCrB * tCrSFB
num_kblocks = cute.size(tCrA, mode=[2])
for kblock_idx in cutlass.range(num_kblocks, unroll_full=True):
kblock_coord = (
None,
None,
kblock_idx,
ab_consumer_state.index,
)
# Set SFA/SFB tensor to tiled_mma
sf_kblock_coord = (None, None, kblock_idx)
tiled_mma.set(
tcgen05.Field.SFA,
tCtSFA[sf_kblock_coord].iterator,
)
tiled_mma.set(
tcgen05.Field.SFB,
tCtSFB_mma[sf_kblock_coord].iterator,
)
cute.gemm(
tiled_mma,
tCtAcc,
tCrA[kblock_coord],
tCrB[kblock_coord],
tCtAcc,
)
# Enable accumulate on tCtAcc after first kblock
tiled_mma.set(tcgen05.Field.ACCUMULATE, True)
# Async arrive AB buffer empty
ab_pipeline.consumer_release(ab_consumer_state)
# Peek (try_wait) AB buffer full for k_tile = k_tile + 1
ab_consumer_state.advance()
peek_ab_full_status = cutlass.Boolean(1)
if ab_consumer_state.count < k_tile_cnt:
if is_leader_cta:
peek_ab_full_status = ab_pipeline.consumer_try_wait(
ab_consumer_state
)
#
# Async arrive accumulator buffer full
#
if is_leader_cta:
acc_pipeline.producer_commit(acc_producer_state)
acc_producer_state.advance()
#
# Advance to next tile
#
tile_sched.advance_to_next_work()
work_tile = tile_sched.get_current_work()
#
# Wait for accumulator buffer empty
#
acc_pipeline.producer_tail(acc_producer_state)
#
# Specialized epilogue warps
#
if warp_idx < self.mma_warp_id:
#
# Alloc tensor memory buffer
#
tmem.allocate(self.num_tmem_alloc_cols)
#
# Bar sync for retrieve tensor memory ptr from shared memory
#
tmem.wait_for_alloc()
#
# Retrieving tensor memory ptr and make accumulator tensor
#
acc_tmem_ptr = tmem.retrieve_ptr(self.acc_dtype)
# (MMA, MMA_M, MMA_N, STAGE)
tCtAcc_base = cute.make_tensor(acc_tmem_ptr, tCtAcc_fake.layout)
#
# Partition for epilogue
#
epi_tidx = tidx
(
tiled_copy_t2r,
tTR_tAcc_base,
tTR_rAcc,
) = self.epilog_tmem_copy_and_partition(
epi_tidx, tCtAcc_base, tCgC, epi_tile, use_2cta_instrs
)
tTR_rC = cute.make_rmem_tensor(tTR_rAcc.shape, self.c_dtype)
tiled_copy_r2s, tRS_rC, tRS_sC = self.epilog_smem_copy_and_partition(
tiled_copy_t2r, tTR_rC, epi_tidx, sC
)
(
tma_atom_c,
bSG_sC,
bSG_gC_partitioned,
) = self.epilog_gmem_copy_and_partition(
epi_tidx, tma_atom_c, tCgC, epi_tile, sC
)
#
# Persistent tile scheduling loop
#
tile_sched = utils.StaticPersistentTileScheduler.create(
tile_sched_params, cute.arch.block_idx(), cute.arch.grid_dim()
)
work_tile = tile_sched.initial_work_tile_info()
acc_consumer_state = pipeline.make_pipeline_state(
pipeline.PipelineUserType.Consumer, self.num_acc_stage
)
# Threads/warps participating in tma store pipeline
c_producer_group = pipeline.CooperativeGroup(
pipeline.Agent.Thread,
32 * len(self.epilog_warp_id),
)
c_pipeline = pipeline.PipelineTmaStore.create(
num_stages=self.num_c_stage,
producer_group=c_producer_group,
)
while work_tile.is_valid_tile:
# Get tile coord from tile scheduler
cur_tile_coord = work_tile.tile_idx
mma_tile_coord_mnl = (
cur_tile_coord[0] // cute.size(tiled_mma.thr_id.shape),
cur_tile_coord[1],
cur_tile_coord[2],
)
#
# Slice to per mma tile index
#
# ((ATOM_V, REST_V), EPI_M, EPI_N)
bSG_gC = bSG_gC_partitioned[
(
None,
None,
None,
*mma_tile_coord_mnl,
)
]
# Get accumulator stage index
if cutlass.const_expr(self.overlapping_accum):
acc_stage_index = acc_consumer_state.phase
reverse_subtile = cutlass.Boolean(True) if acc_stage_index == 0 else cutlass.Boolean(False)
else:
acc_stage_index = acc_consumer_state.index
# Set tensor memory buffer for current tile
# (T2R, T2R_M, T2R_N, EPI_M, EPI_M)
tTR_tAcc = tTR_tAcc_base[
(None, None, None, None, None, acc_stage_index)
]
#
# Wait for accumulator buffer full
#
acc_pipeline.consumer_wait(acc_consumer_state)
tTR_tAcc = cute.group_modes(tTR_tAcc, 3, cute.rank(tTR_tAcc))
bSG_gC = cute.group_modes(bSG_gC, 1, cute.rank(bSG_gC))
#
# Store accumulator to global memory in subtiles
#
subtile_cnt = cute.size(tTR_tAcc.shape, mode=[3])
num_prev_subtiles = tile_sched.num_tiles_executed * subtile_cnt
for subtile_idx in cutlass.range(subtile_cnt):
real_subtile_idx = subtile_idx
if cutlass.const_expr(self.overlapping_accum):
if reverse_subtile:
real_subtile_idx = self.cta_tile_shape_mnk[1] // self.epi_tile_n - 1 - subtile_idx
#
# Load accumulator from tensor memory buffer to register
#
tTR_tAcc_mn = tTR_tAcc[(None, None, None, real_subtile_idx)]
cute.copy(tiled_copy_t2r, tTR_tAcc_mn, tTR_rAcc)
#
# Async arrive accumulator buffer empty ealier when overlapping_accum is enabled
#
if cutlass.const_expr(self.overlapping_accum):
if subtile_idx == self.iter_acc_early_release_in_epilogue:
# Fence for TMEM load
cute.arch.fence_view_async_tmem_load()
with cute.arch.elect_one():
acc_pipeline.consumer_release(acc_consumer_state)
acc_consumer_state.advance()
#
# Convert to C type
#
acc_vec = tiled_copy_r2s.retile(tTR_rAcc).load()
acc_vec = epilogue_op(acc_vec.to(self.c_dtype))
tRS_rC.store(acc_vec)
#
# Store C to shared memory
#
c_buffer = (num_prev_subtiles + real_subtile_idx) % self.num_c_stage
cute.copy(
tiled_copy_r2s,
tRS_rC,
tRS_sC[(None, None, None, c_buffer)],
)
# Fence and barrier to make sure shared memory store is visible to TMA store
cute.arch.fence_proxy(
cute.arch.ProxyKind.async_shared,
space=cute.arch.SharedSpace.shared_cta,
)
self.epilog_sync_barrier.arrive_and_wait()
#
# TMA store C to global memory
#
if warp_idx == self.epilog_warp_id[0]:
cute.copy(
tma_atom_c,
bSG_sC[(None, c_buffer)],
bSG_gC[(None, real_subtile_idx)],
)
# Fence and barrier to make sure shared memory store is visible to TMA store
c_pipeline.producer_commit()
c_pipeline.producer_acquire()
self.epilog_sync_barrier.arrive_and_wait()
#
# Async arrive accumulator buffer empty
#
if cutlass.const_expr(not self.overlapping_accum):
with cute.arch.elect_one():
acc_pipeline.consumer_release(acc_consumer_state)
acc_consumer_state.advance()
#
# Advance to next tile
#
tile_sched.advance_to_next_work()
work_tile = tile_sched.get_current_work()
#
# Dealloc the tensor memory buffer
#
tmem.relinquish_alloc_permit()
self.epilog_sync_barrier.arrive_and_wait()
tmem.free(acc_tmem_ptr)
#
# Wait for C store complete
#
c_pipeline.producer_tail()
def mainloop_s2t_copy_and_partition(
self,
sSF: cute.Tensor,
tSF: cute.Tensor,
) -> Tuple[cute.TiledCopy, cute.Tensor, cute.Tensor]:
"""
Make tiledCopy for smem to tmem load for scale factor tensor, then use it to partition smem memory (source) and tensor memory (destination).
:param sSF: The scale factor tensor in smem
:type sSF: cute.Tensor
:param tSF: The scale factor tensor in tmem
:type tSF: cute.Tensor
:return: A tuple containing (tiled_copy_s2t, tCsSF_compact_s2t, tCtSF_compact_s2t) where:
- tiled_copy_s2t: The tiled copy operation for smem to tmem load for scale factor tensor(s2t)
- tCsSF_compact_s2t: The partitioned scale factor tensor in smem
- tSF_compact_s2t: The partitioned scale factor tensor in tmem
:rtype: Tuple[cute.TiledCopy, cute.Tensor, cute.Tensor]
"""
# (MMA, MMA_MN, MMA_K, STAGE)
tCsSF_compact = cute.filter_zeros(sSF)
# (MMA, MMA_MN, MMA_K)
tCtSF_compact = cute.filter_zeros(tSF)
# Make S2T CopyAtom and tiledCopy
copy_atom_s2t = cute.make_copy_atom(
tcgen05.Cp4x32x128bOp(self.cta_group),
self.sf_dtype,
)
tiled_copy_s2t = tcgen05.make_s2t_copy(copy_atom_s2t, tCtSF_compact)
thr_copy_s2t = tiled_copy_s2t.get_slice(0)
# ((ATOM_V, REST_V), Rest_Tiler, MMA_MN, MMA_K, STAGE)
tCsSF_compact_s2t_ = thr_copy_s2t.partition_S(tCsSF_compact)
# ((ATOM_V, REST_V), Rest_Tiler, MMA_MN, MMA_K, STAGE)
tCsSF_compact_s2t = tcgen05.get_s2t_smem_desc_tensor(
tiled_copy_s2t, tCsSF_compact_s2t_
)
# ((ATOM_V, REST_V), Rest_Tiler, MMA_MN, MMA_K)
tCtSF_compact_s2t = thr_copy_s2t.partition_D(tCtSF_compact)
return tiled_copy_s2t, tCsSF_compact_s2t, tCtSF_compact_s2t
def epilog_tmem_copy_and_partition(
self,
tidx: cutlass.Int32,
tAcc: cute.Tensor,
gC_mnl: cute.Tensor,
epi_tile: cute.Tile,
use_2cta_instrs: Union[cutlass.Boolean, bool],
) -> Tuple[cute.TiledCopy, cute.Tensor, cute.Tensor]:
"""
Make tiledCopy for tensor memory load, then use it to partition tensor memory (source) and register array (destination).
:param tidx: The thread index in epilogue warp groups
:type tidx: cutlass.Int32
:param tAcc: The accumulator tensor to be copied and partitioned
:type tAcc: cute.Tensor
:param gC_mnl: The global tensor C
:type gC_mnl: cute.Tensor
:param epi_tile: The epilogue tiler
:type epi_tile: cute.Tile
:param use_2cta_instrs: Whether use_2cta_instrs is enabled
:type use_2cta_instrs: bool
:return: A tuple containing (tiled_copy_t2r, tTR_tAcc, tTR_rAcc) where:
- tiled_copy_t2r: The tiled copy operation for tmem to register copy(t2r)
- tTR_tAcc: The partitioned accumulator tensor
- tTR_rAcc: The accumulated tensor in register used to hold t2r results
:rtype: Tuple[cute.TiledCopy, cute.Tensor, cute.Tensor]
"""
# Make tiledCopy for tensor memory load
copy_atom_t2r = sm100_utils.get_tmem_load_op(
self.cta_tile_shape_mnk,
self.c_layout,
self.c_dtype,
self.acc_dtype,
epi_tile,
use_2cta_instrs,
)
# (EPI_TILE_M, EPI_TILE_N, EPI_M, EPI_N, STAGE)
tAcc_epi = cute.flat_divide(
tAcc[((None, None), 0, 0, None)],
epi_tile,
)
# (EPI_TILE_M, EPI_TILE_N)
tiled_copy_t2r = tcgen05.make_tmem_copy(
copy_atom_t2r, tAcc_epi[(None, None, 0, 0, 0)]
)
thr_copy_t2r = tiled_copy_t2r.get_slice(tidx)
# (T2R, T2R_M, T2R_N, EPI_M, EPI_M, STAGE)
tTR_tAcc = thr_copy_t2r.partition_S(tAcc_epi)
# (EPI_TILE_M, EPI_TILE_N, EPI_M, EPI_N, RestM, RestN, RestL)
gC_mnl_epi = cute.flat_divide(
gC_mnl[((None, None), 0, 0, None, None, None)], epi_tile
)
# (T2R, T2R_M, T2R_N, EPI_M, EPI_N, RestM, RestN, RestL)
tTR_gC = thr_copy_t2r.partition_D(gC_mnl_epi)
# (T2R, T2R_M, T2R_N)
tTR_rAcc = cute.make_rmem_tensor(
tTR_gC[(None, None, None, 0, 0, 0, 0, 0)].shape, self.acc_dtype
)
return tiled_copy_t2r, tTR_tAcc, tTR_rAcc
def epilog_smem_copy_and_partition(
self,
tiled_copy_t2r: cute.TiledCopy,
tTR_rC: cute.Tensor,
tidx: cutlass.Int32,
sC: cute.Tensor,
) -> Tuple[cute.TiledCopy, cute.Tensor, cute.Tensor]:
"""
Make tiledCopy for shared memory store, then use it to partition register array (source) and shared memory (destination).
:param tiled_copy_t2r: The tiled copy operation for tmem to register copy(t2r)
:type tiled_copy_t2r: cute.TiledCopy
:param tTR_rC: The partitioned accumulator tensor
:type tTR_rC: cute.Tensor
:param tidx: The thread index in epilogue warp groups
:type tidx: cutlass.Int32
:param sC: The shared memory tensor to be copied and partitioned
:type sC: cute.Tensor
:type sepi: cute.Tensor
:return: A tuple containing (tiled_copy_r2s, tRS_rC, tRS_sC) where:
- tiled_copy_r2s: The tiled copy operation for register to smem copy(r2s)
- tRS_rC: The partitioned tensor C (register source)
- tRS_sC: The partitioned tensor C (smem destination)
:rtype: Tuple[cute.TiledCopy, cute.Tensor, cute.Tensor]
"""
copy_atom_r2s = sm100_utils.get_smem_store_op(
self.c_layout, self.c_dtype, self.acc_dtype, tiled_copy_t2r
)
tiled_copy_r2s = cute.make_tiled_copy_D(copy_atom_r2s, tiled_copy_t2r)
# (R2S, R2S_M, R2S_N, PIPE_D)
thr_copy_r2s = tiled_copy_r2s.get_slice(tidx)
tRS_sC = thr_copy_r2s.partition_D(sC)
# (R2S, R2S_M, R2S_N)
tRS_rC = tiled_copy_r2s.retile(tTR_rC)
return tiled_copy_r2s, tRS_rC, tRS_sC
def epilog_gmem_copy_and_partition(
self,
tidx: cutlass.Int32,
atom: Union[cute.CopyAtom, cute.TiledCopy],
gC_mnl: cute.Tensor,
epi_tile: cute.Tile,
sC: cute.Tensor,
) -> Tuple[cute.CopyAtom, cute.Tensor, cute.Tensor]:
"""Make tiledCopy for global memory store, then use it to:
partition shared memory (source) and global memory (destination) for TMA store version.
:param tidx: The thread index in epilogue warp groups
:type tidx: cutlass.Int32
:param atom: The copy_atom_c to be used for TMA store version, or tiled_copy_t2r for none TMA store version
:type atom: cute.CopyAtom or cute.TiledCopy
:param gC_mnl: The global tensor C
:type gC_mnl: cute.Tensor
:param epi_tile: The epilogue tiler
:type epi_tile: cute.Tile
:param sC: The shared memory tensor to be copied and partitioned
:type sC: cute.Tensor
:return: A tuple containing (tma_atom_c, bSG_sC, bSG_gC) where:
- tma_atom_c: The TMA copy atom
- bSG_sC: The partitioned shared memory tensor C
- bSG_gC: The partitioned global tensor C
:rtype: Tuple[cute.CopyAtom, cute.Tensor, cute.Tensor]
"""
# (EPI_TILE_M, EPI_TILE_N, EPI_M, EPI_N, RestM, RestN, RestL)
gC_epi = cute.flat_divide(
gC_mnl[((None, None), 0, 0, None, None, None)], epi_tile
)
tma_atom_c = atom
sC_for_tma_partition = cute.group_modes(sC, 0, 2)
gC_for_tma_partition = cute.group_modes(gC_epi, 0, 2)
# ((ATOM_V, REST_V), EPI_M, EPI_N)
# ((ATOM_V, REST_V), EPI_M, EPI_N, RestM, RestN, RestL)
bSG_sC, bSG_gC = cpasync.tma_partition(
tma_atom_c,
0,
cute.make_layout(1),
sC_for_tma_partition,
gC_for_tma_partition,
)
return tma_atom_c, bSG_sC, bSG_gC
@staticmethod
def _compute_stages(
tiled_mma: cute.TiledMma,
mma_tiler_mnk: Tuple[int, int, int],
a_dtype: Type[cutlass.Numeric],
b_dtype: Type[cutlass.Numeric],
epi_tile: cute.Tile,
c_dtype: Type[cutlass.Numeric],
c_layout: utils.LayoutEnum,
sf_dtype: Type[cutlass.Numeric],
sf_vec_size: int,
smem_capacity: int,
occupancy: int,
) -> Tuple[int, int, int]:
"""Computes the number of stages for A/B/C operands based on heuristics.
:param tiled_mma: The tiled MMA object defining the core computation.
:type tiled_mma: cute.TiledMma
:param mma_tiler_mnk: The shape (M, N, K) of the MMA tiler.
:type mma_tiler_mnk: tuple[int, int, int]
:param a_dtype: Data type of operand A.
:type a_dtype: type[cutlass.Numeric]
:param b_dtype: Data type of operand B.
:type b_dtype: type[cutlass.Numeric]
:param epi_tile: The epilogue tile shape.
:type epi_tile: cute.Tile
:param c_dtype: Data type of operand C (output).
:type c_dtype: type[cutlass.Numeric]
:param c_layout: Layout enum of operand C.
:type c_layout: utils.LayoutEnum
:param sf_dtype: Data type of Scale factor.
:type sf_dtype: type[cutlass.Numeric]
:param sf_vec_size: Scale factor vector size.
:type sf_vec_size: int
:param smem_capacity: Total available shared memory capacity in bytes.
:type smem_capacity: int
:param occupancy: Target number of CTAs per SM (occupancy).
:type occupancy: int
:return: A tuple containing the computed number of stages for:
(ACC stages, A/B operand stages, C stages)
:rtype: tuple[int, int, int]
"""
# ACC stages
num_acc_stage = 1 if mma_tiler_mnk[1] == 256 else 2
# Default C stages
num_c_stage = 2
# Calculate smem layout and size for one stage of A, B, SFA, SFB and C
a_smem_layout_stage_one = sm100_utils.make_smem_layout_a(
tiled_mma,
mma_tiler_mnk,
a_dtype,
1, # a tmp 1 stage is provided
)
b_smem_layout_staged_one = sm100_utils.make_smem_layout_b(
tiled_mma,
mma_tiler_mnk,
b_dtype,
1, # a tmp 1 stage is provided
)
sfa_smem_layout_staged_one = blockscaled_utils.make_smem_layout_sfa(
tiled_mma,
mma_tiler_mnk,
sf_vec_size,
1, # a tmp 1 stage is provided
)
sfb_smem_layout_staged_one = blockscaled_utils.make_smem_layout_sfb(
tiled_mma,
mma_tiler_mnk,
sf_vec_size,
1, # a tmp 1 stage is provided
)
c_smem_layout_staged_one = sm100_utils.make_smem_layout_epi(
c_dtype,
c_layout,
epi_tile,
1,
)
ab_bytes_per_stage = (
cute.size_in_bytes(a_dtype, a_smem_layout_stage_one)
+ cute.size_in_bytes(b_dtype, b_smem_layout_staged_one)
+ cute.size_in_bytes(sf_dtype, sfa_smem_layout_staged_one)
+ cute.size_in_bytes(sf_dtype, sfb_smem_layout_staged_one)
)
mbar_helpers_bytes = 1024
c_bytes_per_stage = cute.size_in_bytes(c_dtype, c_smem_layout_staged_one)
c_bytes = c_bytes_per_stage * num_c_stage
# Calculate A/B/SFA/SFB stages:
# Start with total smem per CTA (capacity / occupancy)
# Subtract reserved bytes and initial C stages bytes
# Divide remaining by bytes needed per A/B/SFA/SFB stage
num_ab_stage = (
smem_capacity // occupancy - (mbar_helpers_bytes + c_bytes)
) // ab_bytes_per_stage
# Refine epilogue stages:
# Calculate remaining smem after allocating for A/B/SFA/SFB stages and reserved bytes
# Add remaining unused smem to epilogue
num_c_stage += (
smem_capacity
- occupancy * ab_bytes_per_stage * num_ab_stage
- occupancy * (mbar_helpers_bytes + c_bytes)
) // (occupancy * c_bytes_per_stage)
return num_acc_stage, num_ab_stage, num_c_stage
@staticmethod
def _compute_grid(
c: cute.Tensor,
cta_tile_shape_mnk: Tuple[int, int, int],
cluster_shape_mn: Tuple[int, int],
max_active_clusters: cutlass.Constexpr,
) -> Tuple[utils.PersistentTileSchedulerParams, Tuple[int, int, int]]:
"""Use persistent tile scheduler to compute the grid size for the output tensor C.
:param c: The output tensor C
:type c: cute.Tensor
:param cta_tile_shape_mnk: The shape (M, N, K) of the CTA tile.
:type cta_tile_shape_mnk: tuple[int, int, int]
:param cluster_shape_mn: Shape of each cluster in M, N dimensions.
:type cluster_shape_mn: tuple[int, int]
:param max_active_clusters: Maximum number of active clusters.
:type max_active_clusters: cutlass.Constexpr
:return: A tuple containing:
- tile_sched_params: Parameters for the persistent tile scheduler.
- grid: Grid shape for kernel launch.
:rtype: Tuple[utils.PersistentTileSchedulerParams, tuple[int, int, int]]
"""
c_shape = cute.slice_(cta_tile_shape_mnk, (None, None, 0))
gc = cute.zipped_divide(c, tiler=c_shape)
num_ctas_mnl = gc[(0, (None, None, None))].shape
cluster_shape_mnl = (*cluster_shape_mn, 1)
tile_sched_params = utils.PersistentTileSchedulerParams(
num_ctas_mnl, cluster_shape_mnl
)
grid = utils.StaticPersistentTileScheduler.get_grid_shape(
tile_sched_params, max_active_clusters
)
return tile_sched_params, grid
@staticmethod
def is_valid_dtypes_and_scale_factor_vec_size(
ab_dtype: Type[cutlass.Numeric],
sf_dtype: Type[cutlass.Numeric],
sf_vec_size: int,
c_dtype: Type[cutlass.Numeric],
) -> bool:
"""
Check if the dtypes and sf_vec_size are valid combinations
:param ab_dtype: The data type of the A and B operands
:type ab_dtype: Type[cutlass.Numeric]
:param sf_dtype: The data type of the scale factor
:type sf_dtype: Type[cutlass.Numeric]
:param sf_vec_size: The vector size of the scale factor
:type sf_vec_size: int
:param c_dtype: The data type of the output tensor
:type c_dtype: Type[cutlass.Numeric]
:return: True if the dtypes and sf_vec_size are valid, False otherwise
:rtype: bool
"""
is_valid = True
# Check valid ab_dtype
if ab_dtype not in {
cutlass.Float4E2M1FN,
cutlass.Float8E5M2,
cutlass.Float8E4M3FN,
}:
is_valid = False
# Check valid sf_vec_size
if sf_vec_size not in {16, 32}:
is_valid = False
# Check valid sf_dtype
if sf_dtype not in {cutlass.Float8E8M0FNU, cutlass.Float8E4M3FN}:
is_valid = False
# Check valid sf_dtype and sf_vec_size combinations
if sf_dtype == cutlass.Float8E4M3FN and sf_vec_size == 32:
is_valid = False
if ab_dtype in {cutlass.Float8E5M2, cutlass.Float8E4M3FN} and sf_vec_size == 16:
is_valid = False
# Check valid c_dtype
if c_dtype not in {
cutlass.Float32,
cutlass.Float16,
cutlass.BFloat16,
cutlass.Float8E5M2,
cutlass.Float8E4M3FN,
}:
is_valid = False
return is_valid
@staticmethod
def is_valid_layouts(
ab_dtype: Type[cutlass.Numeric],
c_dtype: Type[cutlass.Numeric],
a_major: str,
b_major: str,
c_major: str,
) -> bool:
"""
Check if layouts and dtypes are valid combinations
:param ab_dtype: The data type of the A and B operands
:type ab_dtype: Type[cutlass.Numeric]
:param c_dtype: The data type of the output tensor
:type c_dtype: Type[cutlass.Numeric]
:param a_major: The major dimension of the A tensor
:type a_major: str
:param b_major: The major dimension of the B tensor
:type b_major: str
:param c_major: The major dimension of the C tensor
:type c_major: str
:return: True if the layouts are valid, False otherwise
:rtype: bool
"""
is_valid = True
if ab_dtype is cutlass.Float4E2M1FN and not (a_major == "k" and b_major == "k"):
is_valid = False
return is_valid
@staticmethod
def is_valid_mma_tiler_and_cluster_shape(
mma_tiler_mn: Tuple[int, int],
cluster_shape_mn: Tuple[int, int],
) -> bool:
"""
Check if the mma tiler and cluster shape are valid
:param mma_tiler_mn: The (M, N) shape of the MMA instruction tiler
:type mma_tiler_mn: Tuple[int, int]
:param cluster_shape_mn: The (ClusterM, ClusterN) shape of the CTA cluster
:type cluster_shape_mn: Tuple[int, int]
:return: True if the mma tiler and cluster shape are valid, False otherwise
:rtype: bool
"""
is_valid = True
# Skip invalid mma tile shape
if mma_tiler_mn[0] not in [128, 256]:
is_valid = False
if mma_tiler_mn[1] not in [64, 128, 192, 256]:
is_valid = False
# Skip illegal cluster shape
if cluster_shape_mn[0] % (2 if mma_tiler_mn[0] == 256 else 1) != 0:
is_valid = False
# Skip invalid cluster shape
is_power_of_2 = lambda x: x > 0 and (x & (x - 1)) == 0
if (
cluster_shape_mn[0] * cluster_shape_mn[1] > 16
or cluster_shape_mn[0] <= 0
or cluster_shape_mn[1] <= 0
# Special cluster shape check for scale factor multicasts.
# Due to limited size of scale factors, we can't multicast among more than 4 CTAs.
or cluster_shape_mn[0] > 4
or cluster_shape_mn[1] > 4
or not is_power_of_2(cluster_shape_mn[0])
or not is_power_of_2(cluster_shape_mn[1])
):
is_valid = False
return is_valid
@staticmethod
def is_valid_tensor_alignment(
m: int,
n: int,
k: int,
l: int,
ab_dtype: Type[cutlass.Numeric],
c_dtype: Type[cutlass.Numeric],
a_major: str,
b_major: str,
c_major: str,
) -> bool:
"""
Check if the tensor alignment is valid
:param m: The number of rows in the A tensor
:type m: int
:param n: The number of columns in the B tensor
:type n: int
:param k: The number of columns in the A tensor
:type k: int
:param l: The number of columns in the C tensor
:type l: int
:param ab_dtype: The data type of the A and B operands
:type ab_dtype: Type[cutlass.Numeric]
:param c_dtype: The data type of the output tensor
:type c_dtype: Type[cutlass.Numeric]
:param a_major: The major axis of the A tensor
:type a_major: str
:param b_major: The major axis of the B tensor
:type b_major: str
:param c_major: The major axis of the C tensor
:type c_major: str
:return: True if the problem shape is valid, False otherwise
:rtype: bool
"""
is_valid = True
def check_contigous_16B_alignment(dtype, is_mode0_major, tensor_shape):
major_mode_idx = 0 if is_mode0_major else 1
num_major_elements = tensor_shape[major_mode_idx]
num_contiguous_elements = 16 * 8 // dtype.width
return num_major_elements % num_contiguous_elements == 0
if (
not check_contigous_16B_alignment(ab_dtype, a_major == "m", (m, k, l))
or not check_contigous_16B_alignment(ab_dtype, b_major == "n", (n, k, l))
or not check_contigous_16B_alignment(c_dtype, c_major == "m", (m, n, l))
):
is_valid = False
return is_valid
@staticmethod
def can_implement(
ab_dtype: Type[cutlass.Numeric],
sf_dtype: Type[cutlass.Numeric],
sf_vec_size: int,
c_dtype: Type[cutlass.Numeric],
mma_tiler_mn: Tuple[int, int],
cluster_shape_mn: Tuple[int, int],
m: int,
n: int,
k: int,
l: int,
a_major: str,
b_major: str,
c_major: str,
) -> bool:
"""
Check if the gemm can be implemented
:param ab_dtype: The data type of the A and B operands
:type ab_dtype: Type[cutlass.Numeric]
:param sf_dtype: The data type of the scale factor tensor
:type sf_dtype: Type[cutlass.Numeric]
:param sf_vec_size: The vector size
:type sf_vec_size: int
:param c_dtype: The data type of the output tensor
:type c_dtype: Type[cutlass.Numeric]
:param mma_tiler_mn: The (M, N) shape of the MMA instruction tiler
:type mma_tiler_mn: Tuple[int, int]
:param cluster_shape_mn: The (ClusterM, ClusterN) shape of the CTA cluster
:type cluster_shape_mn: Tuple[int, int]
:param m: The number of rows in the A tensor
:type m: int
:param n: The number of columns in the B tensor
:type n: int
:param k: The number of columns in the A tensor
:type k: int
:param l: The number of columns in the C tensor
:type l: int
:param a_major: The major axis of the A tensor
:type a_major: str
:param b_major: The major axis of the B tensor
:type b_major: str
:param c_major: The major axis of the C tensor
:type c_major: str
:return: True if the gemm can be implemented, False otherwise
:rtype: bool
"""
can_implement = True
# Skip unsupported types
if not Sm100BlockScaledPersistentDenseGemmKernel.is_valid_dtypes_and_scale_factor_vec_size(
ab_dtype, sf_dtype, sf_vec_size, c_dtype
):
can_implement = False
# Skip unsupported layouts
if not Sm100BlockScaledPersistentDenseGemmKernel.is_valid_layouts(
ab_dtype, c_dtype, a_major, b_major, c_major
):
can_implement = False
# Skip invalid mma tile shape and cluster shape
if not Sm100BlockScaledPersistentDenseGemmKernel.is_valid_mma_tiler_and_cluster_shape(
mma_tiler_mn, cluster_shape_mn
):
can_implement = False
# Skip illegal problem shape for load/store alignment
if not Sm100BlockScaledPersistentDenseGemmKernel.is_valid_tensor_alignment(
m, n, k, l, ab_dtype, c_dtype, a_major, b_major, c_major
):
can_implement = False
return can_implement
# FP4 data type for A and B
ab_dtype = cutlass.Float4E2M1FN
# FP8 data type for scale factors
sf_dtype = cutlass.Float8E4M3FN
# FP16 output type
c_dtype = cutlass.Float16
# Global cache for compiled kernel
_compiled_kernel_cache = None
# This function is used to compile the kernel once and cache it and then allow users to
# run the kernel multiple times to get more accurate timing results.
def compile_kernel():
"""
Compile the kernel once and cache it.
This should be called before any timing measurements.
Returns:
The compiled kernel function
"""
global _compiled_kernel_cache
if _compiled_kernel_cache is not None:
return _compiled_kernel_cache
# Create CuTe pointers for A/B/C/SFA/SFB via torch tensor data pointer
a_ptr = make_ptr(
ab_dtype, 0, cute.AddressSpace.gmem, assumed_align=16
)
b_ptr = make_ptr(
ab_dtype, 0, cute.AddressSpace.gmem, assumed_align=16
)
c_ptr = make_ptr(
c_dtype, 0, cute.AddressSpace.gmem, assumed_align=16
)
sfa_ptr = make_ptr(
sf_dtype, 0, cute.AddressSpace.gmem, assumed_align=32
)
sfb_ptr = make_ptr(
sf_dtype, 0, cute.AddressSpace.gmem, assumed_align=32
)
sf_vec_size = 16
mma_tiler_mn = (128, 128)
cluster_shape_mn = (1, 1)
# Configure gemm kernel
gemm = Sm100BlockScaledPersistentDenseGemmKernel(
sf_vec_size,
mma_tiler_mn,
cluster_shape_mn,
)
# Compute max active clusters on current device
hardware_info = cutlass.utils.HardwareInfo()
max_active_clusters = hardware_info.get_max_active_clusters(
cluster_shape_mn[0] * cluster_shape_mn[1]
)
# Compile the kernel
_compiled_kernel_cache = cute.compile(gemm, a_ptr, b_ptr, sfa_ptr, sfb_ptr, c_ptr, (0, 0, 0, 0), max_active_clusters)
return _compiled_kernel_cache
def custom_kernel(data: input_t) -> output_t:
"""
Execute the block-scaled GEMM kernel.
This is the main entry point called by the evaluation framework.
It converts PyTorch tensors to CuTe tensors, launches the kernel,
and returns the result.
Args:
data: Tuple of (a, b, sfa_ref, sfb_ref, sfa_permuted, sfb_permuted, c) PyTorch tensors
a: [m, k, l] - Input matrix in float4e2m1fn
b: [n, k, l] - Input vector in float4e2m1fn
sfa_ref: [m, k, l] - Scale factors in float8_e4m3fn, used by reference implementation
sfb_ref: [n, k, l] - Scale factors in float8_e4m3fn, used by reference implementation
sfa_permuted: [32, 4, rest_m, 4, rest_k, l] - Scale factors in float8_e4m3fn
sfb_permuted: [32, 4, rest_n, 4, rest_k, l] - Scale factors in float8_e4m3fn
c: [m, n, l] - Output vector in float16
Returns:
Output tensor c with computed results
"""
a, b, _, _, sfa_permuted, sfb_permuted, c = data
# Ensure kernel is compiled (will use cached version if available)
# To avoid the compilation overhead, we compile the kernel once and cache it.
compiled_func = compile_kernel()
# Get dimensions from MxKxL layout
m, k, l = a.shape
n, _, _ = b.shape
# Torch use e2m1_x2 data type, thus k is halved
k = k * 2
# Create CuTe pointers for A/B/C/SFA/SFB via torch tensor data pointer
a_ptr = make_ptr(
ab_dtype, a.data_ptr(), cute.AddressSpace.gmem, assumed_align=16
)
b_ptr = make_ptr(
ab_dtype, b.data_ptr(), cute.AddressSpace.gmem, assumed_align=16
)
c_ptr = make_ptr(
c_dtype, c.data_ptr(), cute.AddressSpace.gmem, assumed_align=16
)
sfa_ptr = make_ptr(
sf_dtype, sfa_permuted.data_ptr(), cute.AddressSpace.gmem, assumed_align=32
)
sfb_ptr = make_ptr(
sf_dtype, sfb_permuted.data_ptr(), cute.AddressSpace.gmem, assumed_align=32
)
# Execute the compiled kernel
compiled_func(a_ptr, b_ptr, sfa_ptr, sfb_ptr, c_ptr, (m, n, k, l))
return c
# TODO just import this
#######################################################################################
#######################################################################################
#######################################################################################
#######################################################################################
#######################################################################################
#######################################################################################
# Scaling factor vector size
sf_vec_size = 16
# Helper function for ceiling division
def ceil_div(a, b):
return (a + b - 1) // b
def generate_input(
m: int,
n: int,
k: int,
l: int,
seed: int,
):
"""
Generate input tensors for NVFP4 block-scaled GEMM.
Args:
m: Number of rows in matrix A
n: Number of columns in matrix B
k: Number of columns in A and rows of B
l: Batch size
seed: Random seed for reproducibility
Returns:
Tuple of (a, b, scale_a, scale_b, c) where:
a: [m, k, l] - Input matrix in torch.float4e2m1fn_x2 data type
b: [n, k, l] - Input matrix in torch.float4e2m1fn_x2 data type
scale_a: [m, k, l] - Input scale factors in torch.float8e4m3fn data type
scale_b: [n, k, l] - Input scale factors in torch.float8e4m3fn data type
scale_a_permuted: [32, 4, rest_m, 4, rest_k, l] - Input scale factors in torch.float8e4m3fn data type
scale_b_permuted: [32, 4, rest_n, 4, rest_k, l] - Input scale factors in torch.float8e4m3fn data type
c: [m, n, l] - Output matrix in torch.float16 data type
"""
torch.manual_seed(seed)
# Generate uint8 tensor, then convert to float4e2m1fn_x2 data type
a_ref = torch.randint(
-6, 6, (l, m, k // 2), dtype=torch.int8, device="cuda"
).permute(1, 2, 0)
b_ref = torch.randint(
-6, 6, (l, n, k // 2), dtype=torch.int8, device="cuda"
).permute(1, 2, 0)
a_ref = a_ref.view(torch.float4_e2m1fn_x2)
b_ref = b_ref.view(torch.float4_e2m1fn_x2)
# Create float16 output tensor
c_ref = torch.randn((l, m, n), dtype=torch.float16, device="cuda").permute(
1, 2, 0
)
# Helper function to prepare the scale factor tensors for both reference
# kernel and customize kernel. The customized data layout can be found in:
# https://docs.nvidia.com/cuda/cublas/index.html?highlight=fp4#d-block-scaling-factors-layout
def create_scale_factor_tensors(l, mn, sf_k, sf_start_int=-3, sf_end_int=3):
# Create the reference scale factor tensor (mn, sf_k, l) on CPU.
ref_shape = (l, mn, sf_k)
ref_permute_order = (1, 2, 0)
# Init with uint8 tensor, then convert to float8_e4m3fn
ref_f8_random_int = torch.randint(sf_start_int, sf_end_int, ref_shape, dtype=torch.int8, device='cuda')
ref_f8_torch_tensor = ref_f8_random_int.to(dtype=torch.float8_e4m3fn)
# permute to match ref_permute_order
ref_f8_torch_tensor_permuted = ref_f8_torch_tensor.permute(*ref_permute_order)
atom_m = (32, 4)
atom_k = 4
mma_shape = (
l, # batch size
ceil_div(mn, atom_m[0] * atom_m[1]),
ceil_div(sf_k, atom_k),
atom_m[0],
atom_m[1],
atom_k,
)
# Reorder scale factor tensor to (32, 4, rest_m, 4, rest_k, l) layout
# Which is needed by the CuTe customized kernel
mma_permute_order = (3, 4, 1, 5, 2, 0)
reordered_f8_torch_tensor = torch.zeros(mma_shape, dtype=torch.int8, device='cuda').to(dtype=torch.float8_e4m3fn)
# Permute according to mma_permute_order
reordered_f8_torch_tensor = reordered_f8_torch_tensor.permute(*mma_permute_order)
# GPU-side vectorized reordering (replaces slow CPU nested loops)
# Create index grids for all dimensions
i_idx = torch.arange(mn, device='cuda')
j_idx = torch.arange(sf_k, device='cuda')
b_idx = torch.arange(l, device='cuda')
# Create meshgrid for all combinations of (i, j, b)
i_grid, j_grid, b_grid = torch.meshgrid(i_idx, j_idx, b_idx, indexing='ij')
# Calculate target indices in vectorized manner
mm = i_grid // (atom_m[0] * atom_m[1])
mm32 = i_grid % atom_m[0]
mm4 = (i_grid % 128) // atom_m[0]
kk = j_grid // atom_k
kk4 = j_grid % atom_k
# Perform the reordering with advanced indexing (all on GPU)
reordered_f8_torch_tensor[mm32, mm4, mm, kk4, kk, b_grid] = ref_f8_torch_tensor_permuted[i_grid, j_grid, b_grid]
return ref_f8_torch_tensor_permuted.cpu(), reordered_f8_torch_tensor
sf_k = ceil_div(k, sf_vec_size)
sfa_ref_cpu, sfa_ref_permuted = create_scale_factor_tensors(l, m, sf_k)
sfb_ref_cpu, sfb_ref_permuted = create_scale_factor_tensors(l, n, sf_k)
return (a_ref, b_ref, sfa_ref_cpu.to("cuda"), sfb_ref_cpu.to("cuda"), sfa_ref_permuted, sfb_ref_permuted, c_ref)
# Helper function to convert scale factor tensor to blocked format
def to_blocked(input_matrix):
rows, cols = input_matrix.shape
# Please ensure rows and cols are multiples of 128 and 4 respectively
n_row_blocks = ceil_div(rows, 128)
n_col_blocks = ceil_div(cols, 4)
padded = input_matrix
blocks = padded.view(n_row_blocks, 128, n_col_blocks, 4).permute(0, 2, 1, 3)
rearranged = blocks.reshape(-1, 4, 32, 4).transpose(1, 2).reshape(-1, 32, 16)
return rearranged.flatten()
def ref_kernel(
data: input_t,
) -> output_t:
"""
PyTorch reference implementation of NVFP4 block-scaled GEMM.
"""
a_ref, b_ref, sfa_ref_cpu, sfb_ref_cpu, _, _, c_ref = data
# Get dimensions from MxNxL layout
_, _, l = c_ref.shape
# Call torch._scaled_mm to compute the GEMM result
for l_idx in range(l):
# Convert the scale factor tensor to blocked format
scale_a = to_blocked(sfa_ref_cpu[:, :, l_idx])
scale_b = to_blocked(sfb_ref_cpu[:, :, l_idx])
# (m, k) @ (n, k).T -> (m, n)
res = torch._scaled_mm(
a_ref[:, :, l_idx],
b_ref[:, :, l_idx].transpose(0, 1),
scale_a.cuda(),
scale_b.cuda(),
bias=None,
out_dtype=torch.float16,
)
c_ref[:, :, l_idx] = res
return c_ref
#######################################################################################
#######################################################################################
#######################################################################################
#######################################################################################
#######################################################################################
if __name__ == '__main__':
data = generate_input(128, 7168, 2048, 1, 1111)
result = custom_kernel(data).clone()
# print(result)
ref_result = ref_kernel(data)
# print(ref_result)
print(f'max_diff {torch.max(torch.abs(result - ref_result))}')scrolls · 2322 lines total
Source code from GPU Mode and the KernelBot dataset · June 9 Researcher Reciprocity License v1.0
Best evidence level for this revision: reported
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