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cutlass/examples/python/CuTeDSL/blackwell/dense_gemm.py
Junkai-Wu b1d6e2c9b3 v4.3 update. (#2709)
* v4.3 update.

* Update the cute_dsl_api changelog's doc link

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---------

Co-authored-by: Larry Wu <larwu@nvidia.com>
2025-10-21 14:26:30 -04:00

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Python

# Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: BSD-3-Clause
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# modification, are permitted provided that the following conditions are met:
# 1. Redistributions of source code must retain the above copyright notice, this
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# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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import argparse
from typing import Optional, Type, Tuple, Union
import cuda.bindings.driver as cuda
import torch
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.cute.testing as testing
"""
A high-performance batched dense GEMM (C = A * B) example for the NVIDIA Blackwell SM100 architecture
using CUTE DSL.
- Matrix A is MxKxL, L is batch dimension, A can be row-major("K") or column-major("M")
- Matrix B is NxKxL, L is batch dimension, B can be row-major("N") or column-major("K")
- Matrix C is MxNxL, L is batch dimension, C can be row-major("N") or column-major("M")
This GEMM kernel supports the following features:
- Utilizes Tensor Memory Access (TMA) for efficient memory operations
- Utilizes Blackwell's tcgen05.mma for matrix multiply-accumulate (MMA) operations (including 2cta mma instructions)
- Implements TMA multicast with cluster to reduce L2 memory traffic
- Supports multi-stage pipeline to overlap computation and memory access
This GEMM works as follows:
1. Load A and B matrices from global memory (GMEM) to shared memory (SMEM) using TMA operations.
2. Perform matrix multiply-accumulate (MMA) operations using tcgen05.mma instruction.
3. Load completed accumulator from tensor memory (TMEM) to registers (RMEM) using tcgen05.ld.
4. Type convert C matrix to output type.
5. Optionally store C matrix from registers (RMEM) to shared memory (SMEM) to global memory (GMEM) with TMA operations,
or directly store C matrix from registers (RMEM) to global memory (GMEM) without TMA operations.
6. Optionally accept an elementwise lambda function epilogue_op to apply to the output tensor:
e.g., relu can set epilogue_op = lambda x: cute.where(x > 0, x, cute.full_like(x, 0))
SM100 tcgen05.mma instructions operate as follows:
- Read matrix A from SMEM
- Read matrix B from SMEM
- Write accumulator to TMEM
The accumulator in TMEM must then be loaded to registers before writing back to GMEM.
To run this example:
.. code-block:: bash
python examples/blackwell/dense_gemm.py \
--ab_dtype Float16 --c_dtype Float16 --acc_dtype Float32 \
--mma_tiler_mn 256,128 --cluster_shape_mn 2,1 \
--mnkl 8192,8192,8192,1 \
--use_tma_store --use_2cta_instrs
The above example command compute batched gemm with M=8192, N=8192, K=8192,
batch_count=1. The Blackwell tcgen05 MMA tile shape used 2 cta with 256x128
MMA tile and the cluster shape is (2,1). The input, mma accumulator and output
data type are set as fp16, fp32 and fp16, respectively.
To collect performance with NCU profiler:
.. code-block:: bash
ncu python examples/blackwell/dense_gemm.py \
--ab_dtype Float16 --c_dtype Float16 --acc_dtype Float32 \
--mma_tiler_mn 256,128 --cluster_shape_mn 2,1 \
--mnkl 8192,8192,8192,1 \
--use_tma_store --use_2cta_instrs
Constraints:
* Supported input data types: fp16, bf16, tf32, int8, uint8, fp8 (e4m3fn, e5m2),
see detailed valid dtype combinations in below DenseGemmKernel class documentation
* A/B tensor must have the same data type
* Mma tiler M must be 64/128 (use_2cta_instrs=False) or 128/256 (use_2cta_instrs=True)
* Mma tiler N must be 32-256, step 32
* Cluster shape M/N must be positive and power of 2, total cluster size <= 16
* Cluster shape M must be multiple of 2 if use_2cta_instrs=True
* The contiguous dimension of A/B/C tensors must be at least 16 bytes aligned,
i.e, number of elements is a multiple of 4, 8, and 16 for TFloat32,
Float16/BFloat16, and Int8/Uint8/Float8, respectively.
* OOB tiles are not allowed when TMA store is disabled
"""
class DenseGemmKernel:
"""
This class implements batched matrix multiplication (C = A x B) with support for various data types
and architectural features specific to Blackwell GPUs.
:param acc_dtype: Data type for accumulation during computation
:type acc_dtype: type[cutlass.Numeric]
:param use_2cta_instrs: Whether to use CTA group 2 for advanced thread cooperation
:type use_2cta_instrs: bool
:param mma_tiler_mn: Shape of the Matrix Multiply-Accumulate (MMA) tiler (M,N)
:type mma_tiler_mn: Tuple[int, int]
:param cluster_shape_mn: Cluster dimensions (M,N) for parallel processing
:type cluster_shape_mn: Tuple[int, int]
:param use_tma_store: Whether to use Tensor Memory Access (TMA) for storing results
:type use_tma_store: bool
:note: In current version, A and B tensor must have the same data type
- i.e., Float8E4M3FN for A and Float8E5M2 for B is not supported
:note: Supported A/B data types:
- TFloat32
- Float16/BFloat16
- Int8/Uint8
- Float8E4M3FN/Float8E5M2
:note: Supported accumulator data types:
- Float32 (for all floating point A/B data types)
- Float16 (only for fp16 and fp8 A/B data types)
- Int32 (only for uint8/int8 A/B data types)
:note: Supported C data types:
- Float32 (for float32 and int32 accumulator data types)
- Int32 (for float32 and int32 accumulator data types)
- Float16/BFloat16 (for fp16 and fp8 accumulator data types)
- Int8/Uint8 (for uint8/int8 accumulator data types)
- Float8E4M3FN/Float8E5M2 (for float32 accumulator data types)
:note: Constraints:
- MMA tiler M must be 64/128 (use_2cta_instrs=False) or 128/256 (use_2cta_instrs=True)
- MMA tiler N must be 32-256, step 32
- Cluster shape M must be multiple of 2 if use_2cta_instrs=True
- Cluster shape M/N must be positive and power of 2, total cluster size <= 16
Example:
>>> gemm = DenseGemmKernel(
... acc_dtype=cutlass.Float32,
... use_2cta_instrs=True,
... mma_tiler_mn=(128, 128),
... cluster_shape_mn=(2, 2)
... )
>>> gemm(a_tensor, b_tensor, c_tensor, stream)
"""
def __init__(
self,
acc_dtype: Type[cutlass.Numeric],
use_2cta_instrs: bool,
mma_tiler_mn: Tuple[int, int],
cluster_shape_mn: Tuple[int, int],
use_tma_store: bool,
):
"""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.
- mma_tiler_mn: The (M, N) shape of the MMA instruction tiler.
- use_2cta_instrs: Boolean indicating if the tcgen05 MMA variant
with cta_group=2 should be used.
2. Cluster Shape:
- cluster_shape_mn: The (ClusterM, ClusterN) shape of the CTA cluster.
3. Output C tensor store mode:
- use_tma_store: Boolean indicating whether to use Tensor Memory Access (TMA) for storing results.
:param acc_dtype: Data type of the accumulator.
:type acc_dtype: type[cutlass.Numeric]
:param mma_tiler_mn: Tuple (M, N) shape of the MMA instruction.
:type mma_tiler_mn: Tuple[int, int]
:param use_2cta_instrs: Boolean, True to use cta_group=2 MMA variant.
:type use_2cta_instrs: bool
:param cluster_shape_mn: Tuple (ClusterM, ClusterN) shape of the cluster.
:type cluster_shape_mn: Tuple[int, int]
:param use_tma_store: Use Tensor Memory Access (TMA) or normal store for output C tensor.
:type use_tma_store: bool
"""
self.acc_dtype: Type[cutlass.Numeric] = acc_dtype
self.use_2cta_instrs = use_2cta_instrs
self.cluster_shape_mn = cluster_shape_mn
# K dimension is deferred in _setup_attributes
self.mma_tiler_mn = mma_tiler_mn
self.mma_tiler = (*mma_tiler_mn, 1)
self.use_tma_store = use_tma_store
self.cta_group = (
tcgen05.CtaGroup.TWO if self.use_2cta_instrs else tcgen05.CtaGroup.ONE
)
self.occupancy = 1
self.threads_per_cta = 128
self.smem_capacity = utils.get_smem_capacity_in_bytes("sm_100")
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
- Computing epilogue subtile
- Setting up A/B/C stage counts in shared memory
- Computing A/B/C shared memory layout
- Computing tensor memory allocation columns
"""
# Configure tiled mma
tiled_mma = sm100_utils.make_trivial_tiled_mma(
self.a_dtype,
self.a_major_mode,
self.b_major_mode,
self.acc_dtype,
self.cta_group,
self.mma_tiler[:2],
)
# 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_tiler[0],
self.mma_tiler[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],
)
# Compute cluster layout
self.cluster_layout_vmnk = cute.tiled_divide(
cute.make_layout((*self.cluster_shape_mn, 1)),
(tiled_mma.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.is_a_mcast = self.num_mcast_ctas_a > 1
self.is_b_mcast = self.num_mcast_ctas_b > 1
# Compute epilogue subtile
if cutlass.const_expr(self.use_tma_store):
self.epi_tile = sm100_utils.compute_epilogue_tile_shape(
self.cta_tile_shape_mnk,
self.use_2cta_instrs,
self.c_layout,
self.c_dtype,
)
else:
self.epi_tile = self.cta_tile_shape_mnk[:2]
# Setup A/B/C stage count in shared 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.smem_capacity,
self.occupancy,
self.use_tma_store,
)
# Compute A/B/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.c_smem_layout_staged = (
sm100_utils.make_smem_layout_epi(
self.c_dtype,
self.c_layout,
self.epi_tile,
self.num_c_stage,
)
if self.use_tma_store
else None
)
# Compute the number of tensor memory allocation columns
self.num_tmem_alloc_cols = self._compute_num_tmem_alloc_cols(
tiled_mma, self.mma_tiler
)
@cute.jit
def __call__(
self,
a: cute.Tensor,
b: cute.Tensor,
c: cute.Tensor,
stream: cuda.CUstream,
epilogue_op: cutlass.Constexpr = lambda x: x,
):
"""Execute the GEMM operation in steps:
- Setup static attributes
- Setup TMA load/store atoms and tensors
- Compute grid size
- Define shared storage for kernel
- Launch the kernel synchronously
:param a: Input tensor A
:type a: cute.Tensor
:param b: Input tensor B
:type b: cute.Tensor
:param c: Output tensor C
:type c: cute.Tensor
:param stream: CUDA stream for asynchronous execution
:type stream: cuda.CUstream
: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.
:raises AssertionError: If OOB (Out-Of-Bounds) tiles are present when TMA store is disabled.
"""
# Setup static attributes before smem/grid/tma computation
self.a_dtype: Type[cutlass.Numeric] = a.element_type
self.b_dtype: Type[cutlass.Numeric] = b.element_type
self.c_dtype: Type[cutlass.Numeric] = c.element_type
self.a_major_mode = utils.LayoutEnum.from_tensor(a).mma_major_mode()
self.b_major_mode = utils.LayoutEnum.from_tensor(b).mma_major_mode()
self.c_layout = utils.LayoutEnum.from_tensor(c)
# 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()
tiled_mma = sm100_utils.make_trivial_tiled_mma(
self.a_dtype,
self.a_major_mode,
self.b_major_mode,
self.acc_dtype,
self.cta_group,
self.mma_tiler[:2],
)
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,
a_smem_layout,
self.mma_tiler,
tiled_mma,
self.cluster_layout_vmnk.shape,
internal_type=(
cutlass.TFloat32 if a.element_type is cutlass.Float32 else None
),
)
# 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,
b_smem_layout,
self.mma_tiler,
tiled_mma,
self.cluster_layout_vmnk.shape,
internal_type=(
cutlass.TFloat32 if b.element_type is cutlass.Float32 else None
),
)
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)
self.num_tma_load_bytes = (a_copy_size + b_copy_size) * atom_thr_size
# Setup store for C
tma_atom_c = None
tma_tensor_c = None
if cutlass.const_expr(self.use_tma_store):
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,
epi_smem_layout,
self.epi_tile,
)
# Compute grid size
grid = self._compute_grid(c, self.cta_tile_shape_mnk, self.cluster_shape_mn)
# Launch the kernel synchronously
self.kernel(
tiled_mma,
tma_atom_a,
tma_tensor_a,
tma_atom_b,
tma_tensor_b,
tma_atom_c,
tma_tensor_c if self.use_tma_store else c,
self.cluster_layout_vmnk,
self.a_smem_layout_staged,
self.b_smem_layout_staged,
self.c_smem_layout_staged,
self.epi_tile,
epilogue_op,
).launch(
grid=grid,
block=[self.threads_per_cta, 1, 1],
cluster=(*self.cluster_shape_mn, 1),
stream=stream,
)
return
# GPU device kernel
@cute.kernel
def kernel(
self,
tiled_mma: cute.TiledMma,
tma_atom_a: cute.CopyAtom,
mA_mkl: cute.Tensor,
tma_atom_b: cute.CopyAtom,
mB_nkl: cute.Tensor,
tma_atom_c: Optional[cute.CopyAtom],
mC_mnl: cute.Tensor,
cluster_layout_vmnk: cute.Layout,
a_smem_layout_staged: cute.ComposedLayout,
b_smem_layout_staged: cute.ComposedLayout,
c_smem_layout_staged: Union[cute.Layout, cute.ComposedLayout, None],
epi_tile: cute.Tile,
epilogue_op: cutlass.Constexpr,
):
"""
GPU device kernel performing the batched GEMM computation.
"""
warp_idx = cute.arch.warp_idx()
warp_idx = cute.arch.make_warp_uniform(warp_idx)
#
# Prefetch tma descriptor
#
if warp_idx == 0:
cpasync.prefetch_descriptor(tma_atom_a)
cpasync.prefetch_descriptor(tma_atom_b)
if cutlass.const_expr(self.use_tma_store):
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
)
# Coords outside cluster
cta_coord = (bidx, bidy, bidz)
mma_tile_coord_mnl = (
cta_coord[0] // cute.size(tiled_mma.thr_id.shape),
cta_coord[1],
cta_coord[2],
)
# Coords inside cta
tidx, _, _ = cute.arch.thread_idx()
#
# Alloc and init: a+b full/empty, accumulator full, tensor memory dealloc barrier
#
@cute.struct
class SharedStorage:
ab_full_mbar_ptr: cute.struct.MemRange[cutlass.Int64, self.num_ab_stage * 2]
acc_full_mbar_ptr: cute.struct.MemRange[
cutlass.Int64, self.num_acc_stage * 2
]
tmem_dealloc_mbar_ptr: cutlass.Int64
tmem_holding_buf: cutlass.Int32
smem = utils.SmemAllocator()
storage = smem.allocate(SharedStorage)
# 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_producer, ab_consumer = 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,
).make_participants()
# Initialize acc_pipeline (barrier) and states
acc_pipeline_producer_group = pipeline.CooperativeGroup(pipeline.Agent.Thread)
acc_pipeline_consumer_group = pipeline.CooperativeGroup(
pipeline.Agent.Thread, self.threads_per_cta
)
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,
)
acc_producer_state = pipeline.make_pipeline_state(
pipeline.PipelineUserType.Producer, self.num_acc_stage
)
acc_consumer_state = pipeline.make_pipeline_state(
pipeline.PipelineUserType.Consumer, self.num_acc_stage
)
tmem_alloc_barrier = pipeline.NamedBarrier(
barrier_id=0, num_threads=self.threads_per_cta
)
# Tensor memory dealloc barrier init
tmem = utils.TmemAllocator(
storage.tmem_holding_buf,
barrier_for_retrieve=tmem_alloc_barrier,
is_two_cta=use_2cta_instrs,
two_cta_tmem_dealloc_mbar_ptr=storage.tmem_dealloc_mbar_ptr,
)
# Cluster arrive after barrier init
if cute.size(self.cluster_shape_mn) > 1:
cute.arch.cluster_arrive_relaxed()
#
# Setup smem tensor A/B/C
#
# (EPI_TILE_M, EPI_TILE_N, STAGE)
sC = None
if cutlass.const_expr(self.use_tma_store):
sC = smem.allocate_tensor(
element_type=self.c_dtype,
layout=c_smem_layout_staged.outer,
byte_alignment=128,
swizzle=c_smem_layout_staged.inner,
)
# (MMA, MMA_M, MMA_K, STAGE)
sA = smem.allocate_tensor(
element_type=self.a_dtype,
layout=a_smem_layout_staged.outer,
byte_alignment=128,
swizzle=a_smem_layout_staged.inner,
)
# (MMA, MMA_N, MMA_K, STAGE)
sB = smem.allocate_tensor(
element_type=self.b_dtype,
layout=b_smem_layout_staged.outer,
byte_alignment=128,
swizzle=b_smem_layout_staged.inner,
)
#
# Compute multicast mask for A/B buffer full
#
a_full_mcast_mask = None
b_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
)
#
# 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, 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)
# (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_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),
)
#
# 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])
# (MMA, MMA_M, MMA_N)
tCtAcc_fake = tiled_mma.make_fragment_C(acc_shape)
#
# Cluster wait before tensor memory alloc
#
if cute.size(self.cluster_shape_mn) > 1:
cute.arch.cluster_wait()
# Alloc tensor memory buffer
tmem.allocate(self.num_tmem_alloc_cols)
# Barrier before retrieve tensor memory ptr from shared memory
tmem.wait_for_alloc()
tmem_ptr = tmem.retrieve_ptr(self.acc_dtype)
# (MMA, MMA_M, MMA_N)
tCtAcc = cute.make_tensor(tmem_ptr, tCtAcc_fake.layout)
#
# Slice to per mma tile index
#
# ((atom_v, rest_v), RestK)
tAgA = tAgA[(None, mma_tile_coord_mnl[0], None, mma_tile_coord_mnl[2])]
# ((atom_v, rest_v), RestK)
tBgB = tBgB[(None, mma_tile_coord_mnl[1], None, mma_tile_coord_mnl[2])]
#
# Pipelining TMA load A/B and MMA mainloop
#
prefetch_k_tile_cnt = cutlass.min(self.num_ab_stage - 2, k_tile_cnt)
if warp_idx == 0:
#
# Prefetch TMA load A/B
#
for k_tile_idx in cutlass.range(prefetch_k_tile_cnt, unroll=1):
# Conditionally wait for AB buffer empty
producer_handle = ab_producer.acquire_and_advance()
# TMA load A/B
cute.copy(
tma_atom_a,
tAgA[(None, k_tile_idx)],
tAsA[(None, producer_handle.index)],
tma_bar_ptr=producer_handle.barrier,
mcast_mask=a_full_mcast_mask,
)
cute.copy(
tma_atom_b,
tBgB[(None, k_tile_idx)],
tBsB[(None, producer_handle.index)],
tma_bar_ptr=producer_handle.barrier,
mcast_mask=b_full_mcast_mask,
)
peek_ab_full_status = cutlass.Boolean(False)
if is_leader_cta:
peek_ab_full_status = ab_consumer.try_wait()
# Peek (try_wait) AB buffer empty for k_tile = prefetch_k_tile_cnt + k_tile + 1
peek_ab_empty_status = ab_producer.try_acquire()
#
# MMA mainloop
#
for k_tile_idx in cutlass.range(k_tile_cnt):
# Conditionally wait for AB buffer empty
if k_tile_idx < k_tile_cnt - prefetch_k_tile_cnt:
producer_handle = ab_producer.acquire_and_advance(
peek_ab_empty_status
)
# TMA load A/B
cute.copy(
tma_atom_a,
tAgA[(None, producer_handle.count)],
tAsA[(None, producer_handle.index)],
tma_bar_ptr=producer_handle.barrier,
mcast_mask=a_full_mcast_mask,
)
cute.copy(
tma_atom_b,
tBgB[(None, producer_handle.count)],
tBsB[(None, producer_handle.index)],
tma_bar_ptr=producer_handle.barrier,
mcast_mask=b_full_mcast_mask,
)
if is_leader_cta:
# Conditionally wait for AB buffer full
consumer_handle = ab_consumer.wait_and_advance(peek_ab_full_status)
# tCtAcc += tCrA * tCrB
num_kblks = cute.size(tCrA, mode=[2])
for kblk_idx in cutlass.range(num_kblks, unroll_full=True):
kblk_crd = (None, None, kblk_idx, consumer_handle.index)
cute.gemm(
tiled_mma, tCtAcc, tCrA[kblk_crd], tCrB[kblk_crd], tCtAcc
)
# Enable accumulate on tCtAcc after first kblock
tiled_mma.set(tcgen05.Field.ACCUMULATE, True)
# Async arrive AB buffer empty
consumer_handle.release()
# Peek (try_wait) AB buffer empty for k_tile = prefetch_k_tile_cnt + k_tile + 1
peek_ab_empty_status = ab_producer.try_acquire()
# Peek (try_wait) AB buffer full for k_tile = k_tile + 1
peek_ab_full_status = ab_consumer.try_wait()
# Async arrive accumulator buffer full
if is_leader_cta:
acc_pipeline.producer_commit(acc_producer_state)
#
# Epilogue
#
# Release tensor memory allocation lock
tmem.relinquish_alloc_permit()
# Wait for accumulator buffer full
acc_pipeline.consumer_wait(acc_consumer_state)
if cutlass.const_expr(self.use_tma_store):
assert tma_atom_c is not None and sC is not None
self.epilogue_tma_store(
tidx,
warp_idx,
mma_tile_coord_mnl, # type: ignore
tma_atom_c,
tCtAcc,
sC,
tCgC,
epi_tile,
epilogue_op,
)
else:
self.epilogue(tidx, mma_tile_coord_mnl, tCtAcc, tCgC, epi_tile, epilogue_op) # type: ignore
#
# Dealloc the tensor memory buffer
#
pipeline.sync(barrier_id=1)
tmem.free(tmem_ptr)
#
# Wait A/B buffer empty
#
if warp_idx == 0:
ab_producer.tail()
return
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)
tAcc_epi = cute.flat_divide(tAcc[((None, None), 0, 0)], epi_tile)
# (EPI_TILE_M, EPI_TILE_N)
tiled_copy_t2r = tcgen05.make_tmem_copy(
copy_atom_t2r, tAcc_epi[(None, None, 0, 0)]
)
thr_copy_t2r = tiled_copy_t2r.get_slice(tidx)
# (T2R, T2R_M, T2R_N, EPI_M, EPI_M)
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
: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
@cute.jit
def epilogue_tma_store(
self,
epi_tidx: cutlass.Int32,
warp_idx: cutlass.Int32,
mma_tile_coord_mnl: Tuple[cutlass.Int32, cutlass.Int32, cutlass.Int32],
tma_atom_c: cute.CopyAtom,
tCtAcc: cute.Tensor,
sC: cute.Tensor,
tCgC: cute.Tensor,
epi_tile: cute.Tile,
epilogue_op: cutlass.Constexpr,
) -> None:
"""
Epilogue implementation for TMA store version.
:param epi_tidx: Thread index
:type epi_tidx: cutlass.Int32
:param warp_idx: Warp index
:type warp_idx: cutlass.Int32
:param tCtAcc: Partitioned accumulator tensor
:type tCtAcc: cute.Tensor
:param sC: Shared memory C tensor
:type sC: cute.Tensor
:param tCgC: Global memory C tensor
:type tCgC: cute.Tensor
:param epi_tile: Epilogue tile
:type epi_tile: cute.Tile
:param epilogue_op: Epilogue operation
:type epilogue_op: cutlass.Constexpr
:param tma_atom_c: TMA atom for C tensor
:type tma_atom_c: cute.CopyAtom
"""
tiled_copy_t2r, tTR_tAcc, tTR_rAcc = self.epilog_tmem_copy_and_partition(
epi_tidx, tCtAcc, tCgC, epi_tile, self.use_2cta_instrs
)
tTR_tAcc = cute.group_modes(tTR_tAcc, 3, cute.rank(tTR_tAcc))
# ((ATOM_V, REST_V), EPI_M, EPI_N)
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
)
# ((ATOM_V, REST_V), EPI_M, EPI_N, RestM, RestN, RestL)
tCgC_epi = cute.flat_divide(
tCgC[((None, None), 0, 0, None, None, None)], epi_tile
)
# ((ATOM_V, REST_V), EPI_M, EPI_N)
bSG_sC, bSG_gC = cpasync.tma_partition(
tma_atom_c,
0,
cute.make_layout(1),
cute.group_modes(sC, 0, 2),
cute.group_modes(tCgC_epi, 0, 2),
)
bSG_gC = bSG_gC[(None, None, None, *mma_tile_coord_mnl)]
bSG_gC = cute.group_modes(bSG_gC, 1, cute.rank(bSG_gC))
# Initialize tma store c_pipeline
c_producer_group = pipeline.CooperativeGroup(
pipeline.Agent.Thread, self.threads_per_cta
)
c_pipeline = pipeline.PipelineTmaStore.create(
num_stages=self.num_c_stage, producer_group=c_producer_group
)
#
# Store accumulator to global memory in sub-tiles
#
subtile_cnt = cute.size(tTR_tAcc.shape, mode=[3])
for subtile_idx in cutlass.range(subtile_cnt):
#
# Load accumulator from tensor memory buffer to register
#
tTR_tAcc_mn = tTR_tAcc[(None, None, None, subtile_idx)]
cute.copy(tiled_copy_t2r, tTR_tAcc_mn, tTR_rAcc)
#
# Perform epilogue op on accumulator and 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 = 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,
)
pipeline.sync(barrier_id=1)
# TMA store C to global memory
if warp_idx == 0:
cute.copy(
tma_atom_c, bSG_sC[(None, c_buffer)], bSG_gC[(None, subtile_idx)]
)
# Fence and barrier to make sure TMA store is completed to recollect C buffer
c_pipeline.producer_commit()
c_pipeline.producer_acquire()
pipeline.sync(barrier_id=1)
# Wait for C store complete
c_pipeline.producer_tail()
@cute.jit
def epilogue(
self,
epi_tidx: cutlass.Int32,
mma_tile_coord_mnl: Tuple[cutlass.Int32, cutlass.Int32, cutlass.Int32],
tCtAcc: cute.Tensor,
tCgC: cute.Tensor,
epi_tile: cute.Tile,
epilogue_op: cutlass.Constexpr,
) -> None:
"""
Epilogue implementation for non-TMA store version.
:param epi_tidx: Thread index
:type epi_tidx: cutlass.Int32
:param tCtAcc: Partitioned accumulator tensor
:type tCtAcc: cute.Tensor
:param tCgC: Global memory C tensor
:type tCgC: cute.Tensor
:param epi_tile: Epilogue tile
:type epi_tile: cute.Tile
:param epilogue_op: Epilogue operation
:type epilogue_op: cutlass.Constexpr
"""
tiled_copy_t2r, tTR_tAcc, tTR_rAcc = self.epilog_tmem_copy_and_partition(
epi_tidx, tCtAcc, tCgC, epi_tile, self.use_2cta_instrs
)
tTR_tAcc = cute.group_modes(tTR_tAcc, 3, cute.rank(tTR_tAcc))
# ((ATOM_V, REST_V), EPI_M, EPI_N, RestM, RestN, RestL)
tCgC_epi = cute.flat_divide(
tCgC[((None, None), 0, 0, None, None, None)], epi_tile
)
# (T2R, T2R_M, T2R_N, EPI_M, EPI_N, RestM, RestN, RestL)
thr_copy_t2r = tiled_copy_t2r.get_slice(epi_tidx)
tTR_gC = thr_copy_t2r.partition_D(tCgC_epi)
# (T2R, T2R_M, T2R_N)
tTR_rC = cute.make_rmem_tensor(
tTR_gC[(None, None, None, 0, 0, 0, 0, 0)].shape, self.c_dtype
)
simt_atom = cute.make_copy_atom(cute.nvgpu.CopyUniversalOp(), self.c_dtype)
# (T2R, T2R_M, T2R_N, EPI_M, EPI_N)
tTR_gC = tTR_gC[(None, None, None, None, None, *mma_tile_coord_mnl)]
tTR_gC = cute.group_modes(tTR_gC, 3, cute.rank(tTR_gC))
#
# Store accumulator to global memory in sub-tiles
#
subtile_cnt = cute.size(tTR_tAcc.shape, mode=[3])
for subtile_idx in cutlass.range(subtile_cnt):
#
# Load accumulator from tensor memory buffer to register
#
tTR_tAcc_mn = tTR_tAcc[(None, None, None, subtile_idx)]
cute.copy(tiled_copy_t2r, tTR_tAcc_mn, tTR_rAcc)
#
# Perform epilogue op on accumulator and convert to C type
#
acc_vec = tTR_rAcc.load()
acc_vec = epilogue_op(acc_vec.to(self.c_dtype))
tTR_rC.store(acc_vec)
# Store C to global memory
cute.copy(simt_atom, tTR_rC, tTR_gC[(None, None, None, subtile_idx)])
@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,
smem_capacity: int,
occupancy: int,
use_tma_store: bool,
) -> 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 tile.
: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 in global memory.
:type c_layout: utils.LayoutEnum
: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
:param use_tma_store: Whether TMA store is enabled.
:type use_tma_store: bool
:return: A tuple containing the computed number of stages for:
(ACC stages, A/B operand stages, epilogue stages)
:rtype: tuple[int, int, int]
"""
# Default ACC stages
num_acc_stage = 1
# Default C stages
num_c_stage = 2 if use_tma_store else 0
# Calculate smem layout and size for one stage of A, B, 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
)
c_smem_layout_staged_one = (
sm100_utils.make_smem_layout_epi(
c_dtype,
c_layout,
epi_tile,
1,
)
if use_tma_store
else None
)
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)
mbar_helpers_bytes = 1024
c_bytes_per_stage = (
cute.size_in_bytes(c_dtype, c_smem_layout_staged_one)
if use_tma_store
else 0
)
c_bytes = c_bytes_per_stage * num_c_stage
# Calculate A/B 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 stage
num_ab_stage = (
smem_capacity - (occupancy + 1) * (mbar_helpers_bytes + c_bytes)
) // ab_bytes_per_stage
# Refine epilogue stages:
# Calculate remaining smem after allocating for A/B stages and reserved bytes
# Add remaining unused smem to epilogue
if use_tma_store:
num_c_stage += (
smem_capacity
- ab_bytes_per_stage * num_ab_stage
- (occupancy + 1) * (mbar_helpers_bytes + c_bytes)
) // ((occupancy + 1) * 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],
) -> Tuple[int, int, int]:
"""Compute grid shape 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]
:return: Grid shape for kernel launch.
:rtype: tuple[int, int, int]
"""
cluster_shape_mnl = (*cluster_shape_mn, 1)
grid = cute.round_up(
(
cute.ceil_div(c.layout.shape[0], cta_tile_shape_mnk[0]),
cute.ceil_div(c.layout.shape[1], cta_tile_shape_mnk[1]),
c.layout.shape[2],
),
cluster_shape_mnl,
)
return grid
@staticmethod
def _compute_num_tmem_alloc_cols(
tiled_mma: cute.TiledMma, mma_tiler: Tuple[int, int, int]
) -> int:
"""
Compute the number of tensor memory allocation columns.
:param tiled_mma: The tiled MMA object defining the core computation.
:type tiled_mma: cute.TiledMma
:param mma_tiler: The shape (M, N, K) of the MMA tile.
:type mma_tiler: tuple[int, int, int]
:return: The number of tensor memory allocation columns.
:rtype: int
"""
acc_shape = tiled_mma.partition_shape_C(mma_tiler[:2])
tCtAcc_fake = tiled_mma.make_fragment_C(acc_shape)
return sm100_utils.get_num_tmem_alloc_cols(tCtAcc_fake)
def is_valid_dtypes(
self, ab_dtype: Type[cutlass.Numeric], c_dtype: Type[cutlass.Numeric]
) -> bool:
"""
Check if the dtypes are valid
: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]
:return: True if the dtypes are valid, False otherwise
:rtype: bool
"""
valid_ab_dtypes = {
cutlass.Float16,
cutlass.BFloat16,
cutlass.TFloat32,
cutlass.Uint8,
cutlass.Int8,
cutlass.Float8E4M3FN,
cutlass.Float8E5M2,
}
if ab_dtype not in valid_ab_dtypes:
return False
if self.acc_dtype not in {cutlass.Float32, cutlass.Float16, cutlass.Int32}:
return False
# Define compatibility mapping between accumulator type and AB type
acc_ab_compatibility = {
cutlass.Float32: {
cutlass.Float16,
cutlass.BFloat16,
cutlass.TFloat32,
cutlass.Float8E4M3FN,
cutlass.Float8E5M2,
}, # Float32 accumulator supports floating point AB types only
cutlass.Float16: {
cutlass.Float16,
cutlass.Float8E4M3FN,
cutlass.Float8E5M2,
},
cutlass.Int32: {cutlass.Uint8, cutlass.Int8},
}
# Check compatibility between accumulator type and AB type
if ab_dtype not in acc_ab_compatibility[self.acc_dtype]:
return False
# Define compatibility mapping between accumulator type and C type
acc_c_compatibility = {
cutlass.Float32: {
cutlass.Float32,
cutlass.Float16,
cutlass.BFloat16,
cutlass.Float8E4M3FN,
cutlass.Float8E5M2,
cutlass.Int32,
cutlass.Int8,
cutlass.Uint8,
},
cutlass.Float16: {
cutlass.BFloat16,
cutlass.Float16,
},
cutlass.Int32: {
cutlass.BFloat16,
cutlass.Float16,
cutlass.Float32,
cutlass.Int32,
cutlass.Int8,
cutlass.Uint8,
},
}
# Check compatibility between accumulator type and C type
if c_dtype not in acc_c_compatibility[self.acc_dtype]:
return False
return True
def is_valid_mma_tiler_and_cluster_shape(self) -> bool:
"""Check if the mma tiler and cluster shape are valid.
:return: True if the mma tiler and cluster shape are valid, False otherwise
:rtype: bool
"""
is_valid = True
# Skip invalid mma tile shape
if not (
(not self.use_2cta_instrs and self.mma_tiler_mn[0] in [64, 128])
or (self.use_2cta_instrs and self.mma_tiler_mn[0] in [128, 256])
):
is_valid = False
if self.mma_tiler_mn[1] not in range(32, 257, 32):
is_valid = False
# Skip illegal cluster shape
if self.cluster_shape_mn[0] % (2 if self.use_2cta_instrs else 1) != 0:
is_valid = False
# Skip invalid cluster shape
is_power_of_2 = lambda x: x > 0 and (x & (x - 1)) == 0
if (
self.cluster_shape_mn[0] * self.cluster_shape_mn[1] > 16
or self.cluster_shape_mn[0] <= 0
or self.cluster_shape_mn[1] <= 0
or not is_power_of_2(self.cluster_shape_mn[0])
or not is_power_of_2(self.cluster_shape_mn[1])
):
is_valid = False
return is_valid
def is_valid_tensor_alignment(
self,
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
# TODO: move to utils
def check_contiguous_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_contiguous_16B_alignment(ab_dtype, a_major == "m", (m, k, l))
or not check_contiguous_16B_alignment(ab_dtype, b_major == "n", (n, k, l))
or not check_contiguous_16B_alignment(c_dtype, c_major == "m", (m, n, l))
):
is_valid = False
return is_valid
def is_valid_epilog_store_option(self, m: int, n: int) -> bool:
"""
Check if the epilogue store option 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
:return: True if the epilogue store option is valid, False otherwise
:rtype: bool
"""
is_valid = True
# None TMA store version does not have predication, can not support OOB tiles
cta_tile_shape_mn = (
self.mma_tiler_mn[0] // (2 if self.use_2cta_instrs else 1),
self.mma_tiler_mn[1],
)
if not self.use_tma_store:
if not (m % cta_tile_shape_mn[0] == 0 and n % cta_tile_shape_mn[1] == 0):
is_valid = False
return is_valid
def can_implement(self, a: cute.Tensor, b: cute.Tensor, c: cute.Tensor) -> bool:
"""Check if the given tensors can be implemented by this kernel.
:param a: Input tensor A
:type a: cute.Tensor
:param b: Input tensor B
:type b: cute.Tensor
:param c: Output tensor C
:type c: cute.Tensor
:return: True if the gemm supports the given config, False otherwise
:rtype: bool
"""
m, n, k, l = a.shape[0], b.shape[0], a.shape[1], a.shape[2]
# infer a_major, b_major, c_major
is_m_major_a = utils.LayoutEnum.from_tensor(a).is_m_major_a()
is_n_major_b = utils.LayoutEnum.from_tensor(b).is_n_major_b()
is_m_major_c = utils.LayoutEnum.from_tensor(c).is_m_major_c()
a_major = "m" if is_m_major_a else "k"
b_major = "n" if is_n_major_b else "k"
c_major = "m" if is_m_major_c else "n"
can_implement = True
# Skip unsupported types
if not self.is_valid_dtypes(a.element_type, c.element_type):
can_implement = False
# Skip invalid mma tile shape and cluster shape
if not self.is_valid_mma_tiler_and_cluster_shape():
can_implement = False
# Skip illegal problem shape for load/store alignment
if not self.is_valid_tensor_alignment(
m, n, k, l, a.element_type, c.element_type, a_major, b_major, c_major
):
can_implement = False
# Skip invalid epilogue store option
if not self.is_valid_epilog_store_option(m, n):
can_implement = False
return can_implement
def create_tensors(l, m, n, k, a_major, b_major, c_major, ab_dtype, c_dtype):
torch.manual_seed(1111)
a_torch_cpu = cutlass_torch.matrix(l, m, k, a_major == "m", ab_dtype)
b_torch_cpu = cutlass_torch.matrix(l, n, k, b_major == "n", ab_dtype)
c_torch_cpu = cutlass_torch.matrix(l, m, n, c_major == "m", c_dtype)
a_tensor, _ = cutlass_torch.cute_tensor_like(
a_torch_cpu, ab_dtype, is_dynamic_layout=True, assumed_align=16
)
b_tensor, _ = cutlass_torch.cute_tensor_like(
b_torch_cpu, ab_dtype, is_dynamic_layout=True, assumed_align=16
)
c_tensor, c_torch_gpu = cutlass_torch.cute_tensor_like(
c_torch_cpu, c_dtype, is_dynamic_layout=True, assumed_align=16
)
return (
a_tensor,
b_tensor,
c_tensor,
a_torch_cpu,
b_torch_cpu,
c_torch_cpu,
c_torch_gpu,
)
def compare(a_torch_cpu, b_torch_cpu, c_torch_gpu, c_dtype, tolerance):
# Copy gpu result back
kernel_result = c_torch_gpu.cpu()
# Compute reference result
ref = torch.einsum(
"mkl,nkl->mnl",
a_torch_cpu.to(dtype=torch.float32),
b_torch_cpu.to(dtype=torch.float32),
)
# Convert ref to c_dtype
_, ref_torch_gpu = cutlass_torch.cute_tensor_like(
ref, c_dtype, is_dynamic_layout=True, assumed_align=16
)
ref_result = ref_torch_gpu.cpu()
# Assert close results
torch.testing.assert_close(kernel_result, ref_result, atol=tolerance, rtol=1e-05)
def run(
mnkl: Tuple[int, int, int, int],
ab_dtype: Type[cutlass.Numeric],
c_dtype: Type[cutlass.Numeric],
acc_dtype: Type[cutlass.Numeric],
a_major: str,
b_major: str,
c_major: str,
mma_tiler_mn: Tuple[int, int] = (256, 256),
cluster_shape_mn: Tuple[int, int] = (2, 1),
use_2cta_instrs: bool = True,
use_tma_store: bool = True,
tolerance: float = 1e-01,
warmup_iterations: int = 0,
iterations: int = 1,
skip_ref_check: bool = False,
use_cold_l2: bool = False,
**kwargs,
):
"""Execute a batched dense GEMM operation on Blackwell architecture with performance benchmarking.
This function prepares input tensors, configures and launches the GEMM kernel,
optionally performs reference validation, and benchmarks the execution performance.
:param mnkl: Problem size (M, N, K, L)
:type mnkl: Tuple[int, int, int, int]
:param ab_dtype: Data type for input tensors A and B
:type ab_dtype: Type[cutlass.Numeric]
:param c_dtype: Data type for output tensor C
:type c_dtype: Type[cutlass.Numeric]
:param acc_dtype: Data type for accumulation during matrix multiplication
:type acc_dtype: Type[cutlass.Numeric]
:param a_major/b_major/c_major: Memory layout of tensor A/B/C
:type a_major/b_major/c_major: str
:param mma_tiler_mn: MMA tiling size. If not specified in the decorator parameters, the autotuner will use the
default value of (256, 256). Otherwise, the autotuner will use the value specified in the decorator parameters.
:type mma_tiler_mn: Tuple[int, int], optional
:param cluster_shape_mn: Cluster shape. If not specified in the decorator parameters, the autotuner will use the
default value of (2, 1). Otherwise, the autotuner will use the value specified in the decorator parameters.
:type cluster_shape_mn: Tuple[int, int], optional
:param use_2cta_instrs: Whether to use 2CTA instructions. If not specified in the decorator parameters, the autotuner
will use the default value of True. Otherwise, the autotuner will use the value specified in the decorator parameters.
:type use_2cta_instrs: bool, optional
:param use_tma_store: Whether to use TMA store. If not specified in the decorator parameters, the autotuner will use
the default value of True. Otherwise, the autotuner will use the value specified in the decorator parameters.
:type use_tma_store: bool, optional
:param tolerance: Tolerance value for reference validation comparison, defaults to 1e-01
:type tolerance: float, optional
:param warmup_iterations: Number of warmup iterations before benchmarking, defaults to 0
:type warmup_iterations: int, optional
:param iterations: Number of benchmark iterations to run, defaults to 1
:type iterations: int, optional
:param skip_ref_check: Whether to skip reference result validation, defaults to False
:type skip_ref_check: bool, optional
:param use_cold_l2: Whether to use circular buffer strategy to ensure cold L2 cache, defaults to False
:type use_cold_l2: bool, optional
:raises RuntimeError: If CUDA GPU is not available
:raises ValueError: If the configuration is invalid or unsupported by the kernel
:return: Execution time of the GEMM kernel
:rtype: float
"""
print("Running Blackwell Dense GEMM test with:")
print(f"mnkl: {mnkl}")
print(f"AB dtype: {ab_dtype}, C dtype: {c_dtype}, Acc dtype: {acc_dtype}")
print(f"Matrix majors - A: {a_major}, B: {b_major}, C: {c_major}")
print(f"Mma Tiler (M, N): {mma_tiler_mn}, Cluster Shape (M, N): {cluster_shape_mn}")
print(f"2CTA MMA instructions: {'True' if use_2cta_instrs else 'False'}")
print(f"Use TMA Store: {'True' if use_tma_store else 'False'}")
print(f"Tolerance: {tolerance}")
print(f"Warmup iterations: {warmup_iterations}")
print(f"Iterations: {iterations}")
print(f"Skip reference checking: {skip_ref_check}")
print(f"Use cold L2: {'True' if use_cold_l2 else 'False'}")
# Unpack parameters
m, n, k, l = mnkl
if not torch.cuda.is_available():
raise RuntimeError("GPU is required to run this example!")
# Get current CUDA stream from PyTorch
torch_stream = torch.cuda.current_stream()
# Get the raw stream pointer as a CUstream
current_stream = cuda.CUstream(torch_stream.cuda_stream)
a_tensor, b_tensor, c_tensor, a_torch_cpu, b_torch_cpu, c_torch_cpu, c_torch_gpu = (
create_tensors(l, m, n, k, a_major, b_major, c_major, ab_dtype, c_dtype)
)
# Build GEMM object
gemm = DenseGemmKernel(
acc_dtype, use_2cta_instrs, mma_tiler_mn, cluster_shape_mn, use_tma_store
)
# Check if configuration can be implemented
can_implement = gemm.can_implement(a_tensor, b_tensor, c_tensor)
if not can_implement:
raise ValueError(
f"The current config which is invalid/unsupported: use_2cta_instrs = {use_2cta_instrs}, "
f"mma_tiler_mn = {mma_tiler_mn}, cluster_shape_mn = {cluster_shape_mn}, "
f"use_tma_store = {use_tma_store}"
)
max_active_clusters = utils.HardwareInfo().get_max_active_clusters(
cluster_shape_mn[0] * cluster_shape_mn[1]
)
compiled_gemm = cute.compile(gemm, a_tensor, b_tensor, c_tensor, current_stream)
if not skip_ref_check:
compiled_gemm(a_tensor, b_tensor, c_tensor, current_stream)
compare(a_torch_cpu, b_torch_cpu, c_torch_gpu, c_dtype, tolerance)
def generate_tensors():
a_tensor, _ = cutlass_torch.cute_tensor_like(
a_torch_cpu, ab_dtype, is_dynamic_layout=True, assumed_align=16
)
b_tensor, _ = cutlass_torch.cute_tensor_like(
b_torch_cpu, ab_dtype, is_dynamic_layout=True, assumed_align=16
)
c_tensor, _ = cutlass_torch.cute_tensor_like(
c_torch_cpu, c_dtype, is_dynamic_layout=True, assumed_align=16
)
return testing.JitArguments(a_tensor, b_tensor, c_tensor, current_stream)
workspace_count = 1
if use_cold_l2:
one_workspace_bytes = (
a_torch_cpu.numel() * a_torch_cpu.element_size()
+ b_torch_cpu.numel() * b_torch_cpu.element_size()
+ c_torch_cpu.numel() * c_torch_cpu.element_size()
)
workspace_count = testing.get_workspace_count(
one_workspace_bytes, warmup_iterations, iterations
)
exec_time = testing.benchmark(
compiled_gemm,
workspace_generator=generate_tensors,
workspace_count=workspace_count,
stream=current_stream,
warmup_iterations=warmup_iterations,
iterations=iterations,
)
return exec_time # Return execution time in microseconds
if __name__ == "__main__":
def parse_comma_separated_ints(s: str) -> Tuple[int, ...]:
try:
return tuple(int(x.strip()) for x in s.split(","))
except ValueError:
raise argparse.ArgumentTypeError(
"Invalid format. Expected comma-separated integers."
)
parser = argparse.ArgumentParser(description="Example of Dense GEMM on Blackwell.")
parser.add_argument(
"--mnkl",
type=parse_comma_separated_ints,
default=(256, 256, 512, 1),
help="mnkl dimensions (comma-separated)",
)
parser.add_argument(
"--mma_tiler_mn",
type=parse_comma_separated_ints,
default=(128, 128),
help="Mma tile shape (comma-separated)",
)
parser.add_argument(
"--cluster_shape_mn",
type=parse_comma_separated_ints,
default=(1, 1),
help="Cluster shape (comma-separated)",
)
parser.add_argument("--ab_dtype", type=cutlass.dtype, default=cutlass.TFloat32)
parser.add_argument("--c_dtype", type=cutlass.dtype, default=cutlass.Float32)
parser.add_argument("--acc_dtype", type=cutlass.dtype, default=cutlass.Float32)
parser.add_argument(
"--use_2cta_instrs",
action="store_true",
help="Enable 2CTA MMA instructions feature",
)
parser.add_argument("--a_major", choices=["k", "m"], type=str, default="k")
parser.add_argument("--b_major", choices=["k", "n"], type=str, default="k")
parser.add_argument("--c_major", choices=["n", "m"], type=str, default="n")
parser.add_argument(
"--use_tma_store", action="store_true", help="Use tma store or not"
)
parser.add_argument(
"--tolerance", type=float, default=1e-01, help="Tolerance for validation"
)
parser.add_argument(
"--warmup_iterations", type=int, default=0, help="Warmup iterations"
)
parser.add_argument(
"--iterations",
type=int,
default=1,
help="Number of iterations to run the kernel",
)
parser.add_argument(
"--skip_ref_check", action="store_true", help="Skip reference checking"
)
parser.add_argument(
"--use_cold_l2",
action="store_true",
default=False,
help="Use circular buffer tensor sets to ensure L2 cold cache",
)
args = parser.parse_args()
if len(args.mnkl) != 4:
parser.error("--mnkl must contain exactly 4 values")
if len(args.mma_tiler_mn) != 2:
parser.error("--mma_tiler_mn must contain exactly 2 values")
if len(args.cluster_shape_mn) != 2:
parser.error("--cluster_shape_mn must contain exactly 2 values")
run(
args.mnkl,
args.ab_dtype,
args.c_dtype,
args.acc_dtype,
args.a_major,
args.b_major,
args.c_major,
args.mma_tiler_mn,
args.cluster_shape_mn,
args.use_2cta_instrs,
args.use_tma_store,
args.tolerance,
args.warmup_iterations,
args.iterations,
args.skip_ref_check,
args.use_cold_l2,
)
print("PASS")