submission 77598
wolfeheart · python · License unknown
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No package. Vendor the mirrored source: 249 lines, June 9 Researcher Reciprocity License v1.0.
submission_v147c.py
curl "https://kernelindex.com/api/v1/implementations/kernelbot-nvfp4-gemv-77598?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 digestsha256:62fc49e35920203726d25fe3faeb5bd8b71ed673b5c594cb2ab33ef4750eb469
license declaredunknown
license concludedunknown
authorswolfeheart
imported2026-08-26
Techniques
Extracted from the mirrored source by pattern, never inferred. Each row cites its line.
tcgen05
mma_op = tcgen05.MmaMXF4NVF4Op(Kernel source
submission_v147c.py249 lines
"""
v147c: Fix MLIR Context Issue
v147b error: "MLIR function requires a Context"
Solution: Create tiled_mma inside a function, not at module level
Try creating it inside the kernel where MLIR context exists.
"""
import torch
import cutlass
import cutlass.cute as cute
from cutlass.cute.runtime import make_ptr
from cutlass.cute.nvgpu import tcgen05
from cutlass.cute.nvgpu.tcgen05 import OperandSource, CtaGroup
import cutlass.utils.blockscaled_layout as blockscaled_utils
# Data types
ab_dtype = cutlass.Float4E2M1FN
sf_dtype = cutlass.Float8E4M3FN
acc_dtype = cutlass.Float32
c_dtype = cutlass.Float16
sf_vec_size = 16
# Configuration
mma_tiler_mnk = (128, 1, 256)
threads_per_cta = 128
# MMA descriptor (this part is safe at module level)
mma_op = tcgen05.MmaMXF4NVF4Op(
sf_dtype=sf_dtype,
instruction_shape=(128, 16, 64),
cta_group=CtaGroup.ONE,
a_src=OperandSource.SMEM,
)
@cute.kernel
def tcgen05_kernel(
mA_mkl: cute.Tensor,
mB_nkl: cute.Tensor,
mSFA_mkl: cute.Tensor,
mSFB_nkl: cute.Tensor,
mC_mnl: cute.Tensor,
):
"""
v147c: Create tiled_mma inside kernel where context exists
"""
# Create mma_atom and tiled_mma HERE (inside kernel with context)
mma_atom = cute.make_mma_atom(mma_op)
tiled_mma = cute.make_tiled_mma(mma_atom)
bidx, bidy, bidz = cute.arch.block_idx()
tidx, _, _ = cute.arch.thread_idx()
warp_id = tidx // 32
lane_id = tidx % 32
# Tile the input tensors
gA_mkl = cute.local_tile(
mA_mkl, cute.slice_(mma_tiler_mnk, (None, 0, None)), (None, None, None)
)
gSFA_mkl = cute.local_tile(
mSFA_mkl, cute.slice_(mma_tiler_mnk, (None, 0, None)), (None, None, None)
)
gB_nkl = cute.local_tile(
mB_nkl, cute.slice_(mma_tiler_mnk, (0, None, None)), (None, None, None)
)
gSFB_nkl = cute.local_tile(
mSFB_nkl, cute.slice_(mma_tiler_mnk, (0, None, None)), (None, None, None)
)
gC_mnl = cute.local_tile(
mC_mnl, cute.slice_(mma_tiler_mnk, (None, None, 0)), (None, None, None)
)
m_idx = warp_id * 32 + lane_id
valid_idx = m_idx if m_idx < 128 else 0
# Output accumulator
tCgC = gC_mnl[valid_idx, None, bidx, bidy, bidz]
tCgC = cute.make_tensor(tCgC.iterator, 1)
res = cute.zeros_like(tCgC, acc_dtype)
# K-loop
k_tile_cnt = gA_mkl.layout[3].shape
for k_tile in range(k_tile_cnt):
# Load current K-tile
tAgA = gA_mkl[valid_idx, None, bidx, k_tile, bidz]
tBgB = gB_nkl[0, None, bidy, k_tile, bidz]
tAgSFA = gSFA_mkl[valid_idx, None, bidx, k_tile, bidz]
tBgSFB = gSFB_nkl[0, None, bidy, k_tile, bidz]
# Load and convert (v146m pattern)
a_val = tAgA.load().to(acc_dtype)
b_val = tBgB.load().to(acc_dtype)
sfa_val = tAgSFA.load().to(acc_dtype)
sfb_val = tBgSFB.load().to(acc_dtype)
# Store to register memory
tArA = cute.make_rmem_tensor_like(tAgA, acc_dtype)
tBrB = cute.make_rmem_tensor_like(tBgB, acc_dtype)
tArSFA = cute.make_rmem_tensor_like(tAgSFA, acc_dtype)
tBrSFB = cute.make_rmem_tensor_like(tBgSFB, acc_dtype)
tArA.store(a_val)
tBrB.store(b_val)
tArSFA.store(sfa_val)
tBrSFB.store(sfb_val)
# Manual SIMT (working pattern from v146m)
num_blocks = mma_tiler_mnk[2] // 16
for i in cutlass.range_constexpr(num_blocks):
idx = i * 16
scale = tArSFA[idx] * tBrSFB[idx]
sum_ab = acc_dtype(0.0)
# Unrolled sum
sum_ab += tArA[idx + 0] * tBrB[idx + 0]
sum_ab += tArA[idx + 1] * tBrB[idx + 1]
sum_ab += tArA[idx + 2] * tBrB[idx + 2]
sum_ab += tArA[idx + 3] * tBrB[idx + 3]
sum_ab += tArA[idx + 4] * tBrB[idx + 4]
sum_ab += tArA[idx + 5] * tBrB[idx + 5]
sum_ab += tArA[idx + 6] * tBrB[idx + 6]
sum_ab += tArA[idx + 7] * tBrB[idx + 7]
sum_ab += tArA[idx + 8] * tBrB[idx + 8]
sum_ab += tArA[idx + 9] * tBrB[idx + 9]
sum_ab += tArA[idx + 10] * tBrB[idx + 10]
sum_ab += tArA[idx + 11] * tBrB[idx + 11]
sum_ab += tArA[idx + 12] * tBrB[idx + 12]
sum_ab += tArA[idx + 13] * tBrB[idx + 13]
sum_ab += tArA[idx + 14] * tBrB[idx + 14]
sum_ab += tArA[idx + 15] * tBrB[idx + 15]
res += sum_ab * scale
# Store result
if m_idx < 128:
tCgC.store(res.to(c_dtype))
@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,
):
m, _, k, l = problem_size
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)),
),
)
n_padded_128 = 128
b_tensor = cute.make_tensor(
b_ptr,
cute.make_layout(
(n_padded_128, cute.assume(k, 32), l),
stride=(cute.assume(k, 32), 1, cute.assume(n_padded_128 * k, 32)),
),
)
c_tensor = cute.make_tensor(
c_ptr,
cute.make_layout((cute.assume(m, 32), 1, l), stride=(1, 1, m))
)
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)
grid = (
cute.ceil_div(c_tensor.shape[0], 128),
1,
c_tensor.shape[2],
)
tcgen05_kernel(
a_tensor, b_tensor, sfa_tensor, sfb_tensor, c_tensor
).launch(
grid=grid,
block=[threads_per_cta, 1, 1],
cluster=(1, 1, 1),
)
_compiled_kernel_cache = None
def compile_kernel():
global _compiled_kernel_cache
if _compiled_kernel_cache is not None:
return _compiled_kernel_cache
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)
_compiled_kernel_cache = cute.compile(
my_kernel, a_ptr, b_ptr, sfa_ptr, sfb_ptr, c_ptr, (0, 0, 0, 0)
)
return _compiled_kernel_cache
def custom_kernel(data):
"""
v147c: tiled_mma created inside kernel (where context exists)
"""
a, b, _, _, sfa_permuted, sfb_permuted, c = data
compiled_func = compile_kernel()
m, k, l = a.shape
k = k * 2
n = 1
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
)
compiled_func(a_ptr, b_ptr, sfa_ptr, sfb_ptr, c_ptr, (m, n, k, l))
return c
if __name__ == "__main__":
print("v147c: tiled_mma created inside kernel to fix MLIR context issue")
scrolls · 249 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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