submission 69558
mdouglas · python · License unknown
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Vendorable · source mirrored · license unknownView source →
No package. Vendor the mirrored source: 59 lines, June 9 Researcher Reciprocity License v1.0.
submission.py
curl "https://kernelindex.com/api/v1/implementations/kernelbot-nvfp4-gemv-69558?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:e613d0a275ba9459b958e6b57a3134ed4cdbede6381dcdbb1ffe1e985fb7f933
license declaredunknown
license concludedunknown
authorsmdouglas
imported2026-08-15
Techniques
Extracted from the mirrored source by pattern, never inferred. Each row cites its line.
Kernel source
submission.py59 lines
import torch
from task import input_t, output_t
torch._dynamo.config.cache_size_limit = 32
# Helper function to convert scale factor tensor to blocked format
@torch.compile(dynamic=False, mode="reduce-overhead", fullgraph=True)
def to_blocked(input_matrix):
rows, cols = input_matrix.shape
blocks = input_matrix.view(rows // 128, 128, cols // 4, 4).permute(0, 2, 1, 3)
#rearranged = blocks.reshape(-1, 4, 32, 4).transpose(1, 2).reshape(-1, 32, 16)
#return rearranged.flatten()
return blocks.reshape(-1, 4, 32, 4).transpose(1, 2).flatten()
@torch.compile(dynamic=False, mode="reduce-overhead", fullgraph=True)
def _inner(a_ref, b_ref, sfa_ref, sfb_ref, l_idx):
scale_a = to_blocked(sfa_ref[..., l_idx])
scale_b = to_blocked(sfb_ref[..., l_idx])
# (m, k) @ (n, k).T -> (m, n)
return torch._scaled_mm(
a_ref[..., l_idx],
b_ref[..., l_idx].transpose(0, 1),
scale_a,
scale_b,
bias=None,
out_dtype=torch.float16,
)[:, 0]
@torch.compile(mode="max-autotune-no-cudagraphs")
def batched_gemv_impl(a_ref, b_ref, c_ref, sfa_ref, sfb_ref):
_, _, l = b_ref.shape
for l_idx in range(l):
c_ref[:, 0, l_idx] = _inner(a_ref, b_ref, sfa_ref, sfb_ref, l_idx)
return c_ref
def custom_kernel(
data: input_t,
) -> output_t:
"""
PyTorch reference implementation of NVFP4 block-scaled GEMV.
"""
a_ref, b_ref, sfa_ref_cpu, sfb_ref_cpu, _, _, c_ref = data
sfa_ref_gpu = sfa_ref_cpu.cuda()
sfb_ref_gpu = sfb_ref_cpu.cuda()
return batched_gemv_impl(
a_ref,
b_ref,
c_ref,
sfa_ref_gpu,
sfb_ref_gpu,
)
scrolls · 59 lines total
Source code from GPU Mode and the KernelBot dataset · June 9 Researcher Reciprocity License v1.0
Changes from previous submission
Against this author's previous submission submission 69391.
import torchfrom task import input_t, output_t+ torch._dynamo.config.cache_size_limit = 32- # Helper function for ceiling division- def ceil_div(a, b):- return (a + b - 1) // b--# Helper function to convert scale factor tensor to blocked format- @torch.compile()+ @torch.compile(dynamic=False, mode="reduce-overhead", fullgraph=True)def to_blocked(input_matrix):rows, cols = input_matrix.shape+ blocks = input_matrix.view(rows // 128, 128, cols // 4, 4).permute(0, 2, 1, 3)+ #rearranged = blocks.reshape(-1, 4, 32, 4).transpose(1, 2).reshape(-1, 32, 16)+ #return rearranged.flatten()+ return blocks.reshape(-1, 4, 32, 4).transpose(1, 2).flatten()- # 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()--+ @torch.compile(dynamic=False, mode="reduce-overhead", fullgraph=True)def _inner(a_ref, b_ref, sfa_ref, sfb_ref, l_idx):- scale_a = to_blocked(sfa_ref[:, :, l_idx])- scale_b = to_blocked(sfb_ref[:, :, l_idx])+ scale_a = to_blocked(sfa_ref[..., l_idx])+ scale_b = to_blocked(sfb_ref[..., l_idx])+# (m, k) @ (n, k).T -> (m, n)- # (m, k) @ (n, k).T -> (m, n)- res = torch._scaled_mm(- a_ref[:, :, l_idx],- b_ref[:, :, l_idx].transpose(0, 1),+ return torch._scaled_mm(+ a_ref[..., l_idx],+ b_ref[..., l_idx].transpose(0, 1),scale_a,scale_b,bias=None,out_dtype=torch.float16,- )- return res[:, 0]-+ )[:, 0]+++ @torch.compile(mode="max-autotune-no-cudagraphs")+ def batched_gemv_impl(a_ref, b_ref, c_ref, sfa_ref, sfb_ref):+ _, _, l = b_ref.shape++ for l_idx in range(l):+ c_ref[:, 0, l_idx] = _inner(a_ref, b_ref, sfa_ref, sfb_ref, l_idx)++ return c_ref+def custom_kernel(data: input_t,) -> output_t:⋯ 2 unchanged lines"""a_ref, b_ref, sfa_ref_cpu, sfb_ref_cpu, _, _, c_ref = data- # Get dimensions from MxNxL layout- _, _, l = c_ref.shape-sfa_ref_gpu = sfa_ref_cpu.cuda()sfb_ref_gpu = sfb_ref_cpu.cuda()- # Call torch._scaled_mm to compute the GEMV result- for l_idx in range(l):- c_ref[:, 0, l_idx] = _inner(a_ref, b_ref, sfa_ref_gpu, sfb_ref_gpu, l_idx)+ return batched_gemv_impl(+ a_ref,+ b_ref,+ c_ref,+ sfa_ref_gpu,+ sfb_ref_gpu,+ )- return c_ref
scrolls · 90 diff lines total
Best evidence level for this revision: reported
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