submission 188457
Nymph · python · License unknown
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No package. Vendor the mirrored source: 795 lines, June 9 Researcher Reciprocity License v1.0.
submission.py
curl "https://kernelindex.com/api/v1/implementations/kernelbot-nvfp4-gemm-188457?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:b0b294007ec3bbf97a3c0da1aeb5031894f1b2f54a269247c4d24d910d6e93e3
license declaredunknown
license concludedunknown
authorsNymph
imported2026-08-26
Techniques
Extracted from the mirrored source by pattern, never inferred. Each row cites its line.
fused-epilogue
num_threads=32 * 5, # MMA warp + 4 epilogue warpsmbarrier
tmem_alloc_barrier = pipeline.NamedBarrier(persistent-kernel
tile_sched_params: utils.PersistentTileSchedulerParams,shared-memory
a_smem_layout_staged: cute.ComposedLayout,tcgen05
acc_tmem_ptr + tcgen05.find_tmem_tensor_col_offset(tCtAcc),warp-specialization
ab_pipeline_producer_group = pipeline.CooperativeGroup(pipeline.Agent.Thread)Kernel source
submission.py795 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
from cutlass.pipeline import pipeline_init_arrive, pipeline_init_wait
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
# Kernel configuration parameters
# Tile sizes for M, N, K dimensions
# M=128, N=128, K=256 are required for MmaMXF4NVF4Op with block-scaled GEMM
mma_tiler_mnk = (128, 128, 256)
# Shape of the K dimension for the MMA instruction
mma_inst_shape_k = 64
# 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
# Scale factor block size (16 elements share one scale)
sf_vec_size = 16
# Stage numbers for shared memory pipeline
num_acc_stage = 1
num_ab_stage = 5 # Optimal for all benchmark sizes
# Total number of columns in tmem
num_tmem_alloc_cols = 512
# Warp specialization IDs for persistent kernel
# Using 6 warps: 4 epilogue warps (0-3) + 1 MMA warp (4) + 1 TMA warp (5)
mma_warp_id = 4
tma_warp_id = 5
threads_per_cta = 32 * 6 # 192 threads total
# Helper function for ceiling division
def ceil_div(a, b):
return (a + b - 1) // b
# The CuTe persistent kernel for NVFP4 block-scaled GEMM with warp specialization
@cute.kernel
def kernel(
tiled_mma: 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,
mC_mnl: cute.Tensor,
a_smem_layout_staged: cute.ComposedLayout,
b_smem_layout_staged: cute.ComposedLayout,
sfa_smem_layout_staged: cute.Layout,
sfb_smem_layout_staged: cute.Layout,
num_tma_load_bytes: cutlass.Constexpr[int],
tile_sched_params: utils.PersistentTileSchedulerParams,
):
"""
GPU device kernel performing persistent batched GEMM computation with warp specialization.
"""
warp_idx = cute.arch.warp_idx()
warp_idx = cute.arch.make_warp_uniform(warp_idx)
#
# Prefetch TMA descriptors (only TMA warp)
#
if warp_idx == 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)
#
# Setup cta/thread coordinates
#
bidx, bidy, bidz = cute.arch.block_idx()
mma_tile_coord_v = bidx % cute.size(tiled_mma.thr_id.shape) # Always 0 for CtaGroup.ONE
is_leader_cta = mma_tile_coord_v == 0 # Always true for CtaGroup.ONE
tidx, _, _ = cute.arch.thread_idx()
#
# Define shared storage for kernel
#
@cute.struct
class SharedStorage:
ab_full_mbar_ptr: cute.struct.MemRange[cutlass.Int64, num_ab_stage]
ab_empty_mbar_ptr: cute.struct.MemRange[cutlass.Int64, num_ab_stage]
acc_full_mbar_ptr: cute.struct.MemRange[cutlass.Int64, num_acc_stage]
acc_empty_mbar_ptr: cute.struct.MemRange[cutlass.Int64, num_acc_stage]
tmem_holding_buf: cutlass.Int32
smem = utils.SmemAllocator()
storage = smem.allocate(SharedStorage)
# (MMA, MMA_M, MMA_K, STAGE)
sA = smem.allocate_tensor(
element_type=ab_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=ab_dtype,
layout=b_smem_layout_staged.outer,
byte_alignment=128,
swizzle=b_smem_layout_staged.inner,
)
# (MMA, MMA_M, MMA_K, STAGE)
sSFA = smem.allocate_tensor(
element_type=sf_dtype,
layout=sfa_smem_layout_staged,
byte_alignment=128,
)
# (MMA, MMA_N, MMA_K, STAGE)
sSFB = smem.allocate_tensor(
element_type=sf_dtype,
layout=sfb_smem_layout_staged,
byte_alignment=128,
)
#
# Initialize pipelines (with defer_sync=True for manual cluster sync)
#
cluster_layout_vmnk = cute.tiled_divide(
cute.make_layout((1, 1, 1)),
(tiled_mma.thr_id.shape,),
)
# AB pipeline - TMA warp produces, MMA warp consumes
ab_pipeline_producer_group = pipeline.CooperativeGroup(pipeline.Agent.Thread)
ab_pipeline_consumer_group = pipeline.CooperativeGroup(pipeline.Agent.Thread, 1)
ab_pipeline = pipeline.PipelineTmaUmma.create(
barrier_storage=storage.ab_full_mbar_ptr.data_ptr(),
num_stages=num_ab_stage,
producer_group=ab_pipeline_producer_group,
consumer_group=ab_pipeline_consumer_group,
tx_count=num_tma_load_bytes,
cta_layout_vmnk=cluster_layout_vmnk,
defer_sync=True,
)
# Accumulator pipeline - MMA warp produces, epilogue warps consume
acc_pipeline_producer_group = pipeline.CooperativeGroup(pipeline.Agent.Thread)
# 4 epilogue warps = warp 0,1,2,3
num_epilog_warps = 4
acc_pipeline_consumer_group = pipeline.CooperativeGroup(
pipeline.Agent.Thread, num_epilog_warps
)
acc_pipeline = pipeline.PipelineUmmaAsync.create(
barrier_storage=storage.acc_full_mbar_ptr.data_ptr(),
num_stages=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 allocation barrier (MMA warp + epilogue warps = 5 warps)
tmem_alloc_barrier = pipeline.NamedBarrier(
barrier_id=1,
num_threads=32 * 5, # MMA warp + 4 epilogue warps
)
# Epilogue sync barrier (only epilogue warps = 4 warps)
epilog_sync_barrier = pipeline.NamedBarrier(
barrier_id=2,
num_threads=32 * 4, # Only 4 epilogue warps
)
tmem = utils.TmemAllocator(
storage.tmem_holding_buf,
barrier_for_retrieve=tmem_alloc_barrier,
allocator_warp_id=0, # First epilogue warp allocates
)
# Cluster sync after barrier init
pipeline_init_arrive(cluster_shape_mn=(1, 1), is_relaxed=True)
#
# Local_tile partition global tensors
#
# (bM, bK, RestM, RestK, RestL)
gA_mkl = cute.local_tile(
mA_mkl, cute.slice_(mma_tiler_mnk, (None, 0, None)), (None, None, None)
)
# (bN, bK, RestN, RestK, RestL)
gB_nkl = cute.local_tile(
mB_nkl, cute.slice_(mma_tiler_mnk, (0, None, None)), (None, None, None)
)
gSFA_mkl = cute.local_tile(
mSFA_mkl, cute.slice_(mma_tiler_mnk, (None, 0, None)), (None, None, None)
)
gSFB_nkl = cute.local_tile(
mSFB_nkl, cute.slice_(mma_tiler_mnk, (0, None, None)), (None, None, None)
)
# (bM, bN, RestM, RestN, RestL)
gC_mnl = cute.local_tile(
mC_mnl, cute.slice_(mma_tiler_mnk, (None, None, 0)), (None, None, None)
)
k_tile_cnt = cute.size(gA_mkl, mode=[3])
#
# Partition global tensor for TiledMMA
#
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_K, RestM, RestK, RestL)
tCgSFA = thr_mma.partition_A(gSFA_mkl)
# (MMA, MMA_N, MMA_K, RestN, RestK, RestL)
tCgSFB = thr_mma.partition_B(gSFB_nkl)
# (MMA, MMA_M, MMA_N, RestM, RestN, RestL)
tCgC = thr_mma.partition_C(gC_mnl)
#
# TMA Partition for A/B/SFA/SFB
#
# TMA Partition_S/D for A
tAsA, tAgA = cpasync.tma_partition(
tma_atom_a,
0,
cute.make_layout(1),
cute.group_modes(sA, 0, 3),
cute.group_modes(tCgA, 0, 3),
)
# TMA Partition_S/D for B
tBsB, tBgB = cpasync.tma_partition(
tma_atom_b,
0,
cute.make_layout(1),
cute.group_modes(sB, 0, 3),
cute.group_modes(tCgB, 0, 3),
)
# TMA Partition_S/D for SFA
tAsSFA, tAgSFA = cpasync.tma_partition(
tma_atom_sfa,
0,
cute.make_layout(1),
cute.group_modes(sSFA, 0, 3),
cute.group_modes(tCgSFA, 0, 3),
)
tAsSFA = cute.filter_zeros(tAsSFA)
tAgSFA = cute.filter_zeros(tAgSFA)
# TMA Partition_S/D for SFB
tBsSFB, tBgSFB = cpasync.tma_partition(
tma_atom_sfb,
0,
cute.make_layout(1),
cute.group_modes(sSFB, 0, 3),
cute.group_modes(tCgSFB, 0, 3),
)
tBsSFB = cute.filter_zeros(tBsSFB)
tBgSFB = cute.filter_zeros(tBgSFB)
#
# Partition 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(mma_tiler_mnk[:2])
tCtAcc_fake = tiled_mma.make_fragment_C(acc_shape)
#
# Cluster wait before tensor memory alloc
#
pipeline_init_wait(cluster_shape_mn=(1, 1))
# =====================================================================
# SPECIALIZED TMA WARP - Handles all TMA loads
# =====================================================================
if warp_idx == tma_warp_id:
# Create tile scheduler
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, num_ab_stage
)
while work_tile.is_valid_tile:
# Get tile coordinates from 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 tile index
tAgA_slice = tAgA[(None, mma_tile_coord_mnl[0], None, mma_tile_coord_mnl[2])]
tBgB_slice = tBgB[(None, mma_tile_coord_mnl[1], None, mma_tile_coord_mnl[2])]
tAgSFA_slice = tAgSFA[(None, mma_tile_coord_mnl[0], None, mma_tile_coord_mnl[2])]
tBgSFB_slice = tBgSFB[(None, mma_tile_coord_mnl[1], None, mma_tile_coord_mnl[2])]
# Reset state for new tile
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 range(k_tile_cnt):
# 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),
)
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),
)
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),
)
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),
)
# Advance and peek next
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 for all buffers to be released
ab_pipeline.producer_tail(ab_producer_state)
# =====================================================================
# SPECIALIZED MMA WARP - Handles all matrix multiply-accumulate
# =====================================================================
if warp_idx == mma_warp_id:
# Wait for TMEM allocation
tmem.wait_for_alloc()
# Retrieve TMEM pointer and make accumulator tensor
acc_tmem_ptr = tmem.retrieve_ptr(cutlass.Float32)
tCtAcc = cute.make_tensor(acc_tmem_ptr, tCtAcc_fake.layout)
# Make SFA/SFB tmem tensors
sfa_tmem_ptr = cute.recast_ptr(
acc_tmem_ptr + tcgen05.find_tmem_tensor_col_offset(tCtAcc),
dtype=sf_dtype,
)
tCtSFA_layout = blockscaled_utils.make_tmem_layout_sfa(
tiled_mma,
mma_tiler_mnk,
sf_vec_size,
cute.slice_(sfa_smem_layout_staged, (None, None, None, 0)),
)
tCtSFA = cute.make_tensor(sfa_tmem_ptr, tCtSFA_layout)
sfb_tmem_ptr = cute.recast_ptr(
acc_tmem_ptr
+ tcgen05.find_tmem_tensor_col_offset(tCtAcc)
+ tcgen05.find_tmem_tensor_col_offset(tCtSFA),
dtype=sf_dtype,
)
tCtSFB_layout = blockscaled_utils.make_tmem_layout_sfb(
tiled_mma,
mma_tiler_mnk,
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
copy_atom_s2t = cute.make_copy_atom(
tcgen05.Cp4x32x128bOp(tcgen05.CtaGroup.ONE),
sf_dtype,
)
tCsSFA_compact = cute.filter_zeros(sSFA)
tCtSFA_compact = cute.filter_zeros(tCtSFA)
tiled_copy_s2t_sfa = tcgen05.make_s2t_copy(copy_atom_s2t, tCtSFA_compact)
thr_copy_s2t_sfa = tiled_copy_s2t_sfa.get_slice(0)
tCsSFA_compact_s2t_ = thr_copy_s2t_sfa.partition_S(tCsSFA_compact)
tCsSFA_compact_s2t = tcgen05.get_s2t_smem_desc_tensor(
tiled_copy_s2t_sfa, tCsSFA_compact_s2t_
)
tCtSFA_compact_s2t = thr_copy_s2t_sfa.partition_D(tCtSFA_compact)
tCsSFB_compact = cute.filter_zeros(sSFB)
tCtSFB_compact = cute.filter_zeros(tCtSFB)
tiled_copy_s2t_sfb = tcgen05.make_s2t_copy(copy_atom_s2t, tCtSFB_compact)
thr_copy_s2t_sfb = tiled_copy_s2t_sfb.get_slice(0)
tCsSFB_compact_s2t_ = thr_copy_s2t_sfb.partition_S(tCsSFB_compact)
tCsSFB_compact_s2t = tcgen05.get_s2t_smem_desc_tensor(
tiled_copy_s2t_sfb, tCsSFB_compact_s2t_
)
tCtSFB_compact_s2t = thr_copy_s2t_sfb.partition_D(tCtSFB_compact)
# Create tile scheduler
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, num_ab_stage
)
acc_producer_state = pipeline.make_pipeline_state(
pipeline.PipelineUserType.Producer, num_acc_stage
)
num_kblocks = cute.size(tCrA, mode=[2])
while work_tile.is_valid_tile:
# Reset state for new tile
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)
# Reset accumulate flag for new tile
tiled_mma.set(tcgen05.Field.ACCUMULATE, False)
# MMA mainloop
for k_tile in range(k_tile_cnt):
if is_leader_cta:
# 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)
cute.copy(
tiled_copy_s2t_sfa,
tCsSFA_compact_s2t[s2t_stage_coord],
tCtSFA_compact_s2t,
)
cute.copy(
tiled_copy_s2t_sfb,
tCsSFB_compact_s2t[s2t_stage_coord],
tCtSFB_compact_s2t,
)
# MMA computation
for kblock_idx in cutlass.range(num_kblocks, unroll_full=True):
kblock_coord = (None, None, kblock_idx, ab_consumer_state.index)
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[sf_kblock_coord].iterator)
cute.gemm(
tiled_mma,
tCtAcc,
tCrA[kblock_coord],
tCrB[kblock_coord],
tCtAcc,
)
tiled_mma.set(tcgen05.Field.ACCUMULATE, True)
# Release buffer
ab_pipeline.consumer_release(ab_consumer_state)
# Advance and peek next (outside is_leader_cta check per reference example)
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)
# Commit accumulator
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 (warp_idx < mma_warp_id) - Handle storing results
# =====================================================================
if warp_idx < mma_warp_id:
# Allocate TMEM (only warp 0 actually allocates, but all participate in barrier)
tmem.allocate(num_tmem_alloc_cols)
tmem.wait_for_alloc()
# Retrieve TMEM pointer
acc_tmem_ptr = tmem.retrieve_ptr(cutlass.Float32)
tCtAcc_base = cute.make_tensor(acc_tmem_ptr, tCtAcc_fake.layout)
# Partition for epilogue
op = tcgen05.Ld32x32bOp(tcgen05.Repetition.x128, tcgen05.Pack.NONE)
copy_atom_t2r = cute.make_copy_atom(op, cutlass.Float32)
tiled_copy_t2r = tcgen05.make_tmem_copy(copy_atom_t2r, tCtAcc_base)
thr_copy_t2r = tiled_copy_t2r.get_slice(tidx)
tTR_tAcc = thr_copy_t2r.partition_S(tCtAcc_base)
tTR_gC = thr_copy_t2r.partition_D(tCgC)
tTR_rAcc = cute.make_rmem_tensor(
tTR_gC[None, None, None, None, 0, 0, 0].shape, cutlass.Float32
)
tTR_rC = cute.make_rmem_tensor(
tTR_gC[None, None, None, None, 0, 0, 0].shape, c_dtype
)
simt_atom = cute.make_copy_atom(cute.nvgpu.CopyUniversalOp(), c_dtype)
# Create tile scheduler
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, num_acc_stage
)
while work_tile.is_valid_tile:
# Get tile coordinates
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],
)
# Wait for accumulator buffer full
acc_pipeline.consumer_wait(acc_consumer_state)
# Copy accumulator to register
tTR_gC_slice = tTR_gC[(None, None, None, None, *mma_tile_coord_mnl)]
cute.copy(tiled_copy_t2r, tTR_tAcc, tTR_rAcc)
acc_vec = tTR_rAcc.load().to(c_dtype)
tTR_rC.store(acc_vec)
# Store C to global memory
cute.copy(simt_atom, tTR_rC, tTR_gC_slice)
# Release accumulator buffer (only one thread releases)
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()
# Free TMEM
tmem.relinquish_alloc_permit()
epilog_sync_barrier.arrive_and_wait()
tmem.free(acc_tmem_ptr)
return
@cute.jit
def my_kernel(
a_ptr: cute.Pointer,
b_ptr: cute.Pointer,
sfa_ptr: cute.Pointer,
sfb_ptr: cute.Pointer,
c_ptr: cute.Pointer,
problem_size: tuple,
):
"""
Host-side JIT function to prepare tensors and launch GPU kernel.
"""
m, n, k, l = problem_size
# Setup attributes that depend on gemm inputs
a_tensor = cute.make_tensor(
a_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_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_ptr, cute.make_layout((cute.assume(m, 32), n, l), stride=(n, 1, m * n))
)
# Setup sfa/sfb tensor
sfa_layout = blockscaled_utils.tile_atom_to_shape_SF(a_tensor.shape, sf_vec_size)
sfa_tensor = cute.make_tensor(sfa_ptr, sfa_layout)
sfb_layout = blockscaled_utils.tile_atom_to_shape_SF(b_tensor.shape, sf_vec_size)
sfb_tensor = cute.make_tensor(sfb_ptr, sfb_layout)
mma_op = tcgen05.MmaMXF4NVF4Op(
sf_dtype,
(mma_tiler_mnk[0], mma_tiler_mnk[1], mma_inst_shape_k),
tcgen05.CtaGroup.ONE,
tcgen05.OperandSource.SMEM,
)
tiled_mma = cute.make_tiled_mma(mma_op)
cluster_layout_vmnk = cute.tiled_divide(
cute.make_layout((1, 1, 1)),
(tiled_mma.thr_id.shape,),
)
# Compute A/B/SFA/SFB/C shared memory layout
a_smem_layout_staged = sm100_utils.make_smem_layout_a(
tiled_mma, mma_tiler_mnk, ab_dtype, num_ab_stage
)
b_smem_layout_staged = sm100_utils.make_smem_layout_b(
tiled_mma, mma_tiler_mnk, ab_dtype, num_ab_stage
)
sfa_smem_layout_staged = blockscaled_utils.make_smem_layout_sfa(
tiled_mma, mma_tiler_mnk, sf_vec_size, num_ab_stage
)
sfb_smem_layout_staged = blockscaled_utils.make_smem_layout_sfb(
tiled_mma, mma_tiler_mnk, sf_vec_size, num_ab_stage
)
atom_thr_size = cute.size(tiled_mma.thr_id.shape)
# Setup TMA for A
a_smem_layout = cute.slice_(a_smem_layout_staged, (None, None, None, 0))
tma_atom_a, tma_tensor_a = cute.nvgpu.make_tiled_tma_atom_A(
cpasync.CopyBulkTensorTileG2SOp(tcgen05.CtaGroup.ONE),
a_tensor,
a_smem_layout,
mma_tiler_mnk,
tiled_mma,
cluster_layout_vmnk.shape,
)
# Setup TMA for B
b_smem_layout = cute.slice_(b_smem_layout_staged, (None, None, None, 0))
tma_atom_b, tma_tensor_b = cute.nvgpu.make_tiled_tma_atom_B(
cpasync.CopyBulkTensorTileG2SOp(tcgen05.CtaGroup.ONE),
b_tensor,
b_smem_layout,
mma_tiler_mnk,
tiled_mma,
cluster_layout_vmnk.shape,
)
# Setup TMA for SFA
sfa_smem_layout = cute.slice_(sfa_smem_layout_staged, (None, None, None, 0))
tma_atom_sfa, tma_tensor_sfa = cute.nvgpu.make_tiled_tma_atom_A(
cpasync.CopyBulkTensorTileG2SOp(tcgen05.CtaGroup.ONE),
sfa_tensor,
sfa_smem_layout,
mma_tiler_mnk,
tiled_mma,
cluster_layout_vmnk.shape,
internal_type=cutlass.Int16,
)
# Setup TMA for SFB
sfb_smem_layout = cute.slice_(sfb_smem_layout_staged, (None, None, None, 0))
tma_atom_sfb, tma_tensor_sfb = cute.nvgpu.make_tiled_tma_atom_B(
cpasync.CopyBulkTensorTileG2SOp(tcgen05.CtaGroup.ONE),
sfb_tensor,
sfb_smem_layout,
mma_tiler_mnk,
tiled_mma,
cluster_layout_vmnk.shape,
internal_type=cutlass.Int16,
)
# Compute TMA load bytes
a_copy_size = cute.size_in_bytes(ab_dtype, a_smem_layout)
b_copy_size = cute.size_in_bytes(ab_dtype, b_smem_layout)
sfa_copy_size = cute.size_in_bytes(sf_dtype, sfa_smem_layout)
sfb_copy_size = cute.size_in_bytes(sf_dtype, sfb_smem_layout)
num_tma_load_bytes = (
a_copy_size + b_copy_size + sfa_copy_size + sfb_copy_size
) * atom_thr_size
# Compute grid size using persistent tile scheduler
cta_tile_shape_mnk = (
mma_tiler_mnk[0] // cute.size(tiled_mma.thr_id.shape),
mma_tiler_mnk[1],
mma_tiler_mnk[2],
)
cluster_shape_mn = (1, 1)
max_active_clusters = 148 # B200 has 148 SMs
# Compute number of CTAs in M, N, L dimensions
c_shape_mn = cute.slice_(cta_tile_shape_mnk, (None, None, 0))
gc = cute.zipped_divide(c_tensor, tiler=c_shape_mn)
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
)
# Launch the kernel
kernel(
tiled_mma,
tma_atom_a, tma_tensor_a,
tma_atom_b, tma_tensor_b,
tma_atom_sfa, tma_tensor_sfa,
tma_atom_sfb, tma_tensor_sfb,
c_tensor,
a_smem_layout_staged,
b_smem_layout_staged,
sfa_smem_layout_staged,
sfb_smem_layout_staged,
num_tma_load_bytes,
tile_sched_params,
).launch(
grid=grid,
block=[threads_per_cta, 1, 1],
cluster=(*cluster_shape_mn, 1),
)
return
# Global cache for compiled kernel
_compiled_kernel = None
def compile_kernel():
"""Compile the kernel."""
global _compiled_kernel
if _compiled_kernel is not None:
return _compiled_kernel
# Create CuTe pointers
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)
# Compile the kernel
_compiled_kernel = cute.compile(my_kernel, a_ptr, b_ptr, sfa_ptr, sfb_ptr, c_ptr, (0, 0, 0, 0))
return _compiled_kernel
def custom_kernel(data: input_t) -> output_t:
"""Execute the block-scaled GEMM kernel."""
a, b, _, _, sfa_permuted, sfb_permuted, c = data
# Get dimensions
m, k, l = a.shape
n, _, _ = b.shape
k = k * 2 # Torch uses e2m1_x2 data type
# Get compiled kernel
compiled_func = compile_kernel()
# Create CuTe pointers
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 kernel
compiled_func(a_ptr, b_ptr, sfa_ptr, sfb_ptr, c_ptr, (m, n, k, l))
return c
scrolls · 795 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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