Grouped GEMM mxfp8 MXFP4 g4 n4096 k2048
2 eligible runs
gemm
Groupwise MXFP8 x MXFP4 GEMM (4 equal groups, N=4096, K=2048). A is MXFP8 (float8_e4m3fn + UE8M0 per-32 block scale), B is per-group MXFP4 (packed E2M1 + UE8M0 per-32 block scale). Groups are concatenated along M with boundaries in m_indptr. Reference dequantizes per group and matmuls; the kernel is exact against it.
Source baseline · unbeaten
321.8µsmean
group_gemm_mxfp4_flashinfer_g4_n4096_k2048FlashInfer-Bench baselines · Apache-2.0 · python
Reported evidence · last observed 2026-06-06. The source's designated baseline implementation. Reported by source; not independently reproduced.
Current records
Not measured on H100 for this workload. Challenges →
Source-native comparison · GPU NVIDIA B200 · Workload m = 512 · fp8_e4m3 · CUDA 13.0 · Framework pytorch 2.11.0+cu130 · Protocol flashinfer-bench · mean · 1 results · last observed 2026-06-06Record history →
Estimated floor 2.36 µs · record 136.16× above itestimate, not evidence ›
DRAM 2.36 µs · compute 1.91 µs · bandwidth-bound on B200
every declared tensor crosses HBM exactly once (8,000 GB/s, B200 datasheet)
2·M·N·K with M=512, N=4096, K=2048 at the dense fp8 peak (4,500 TFLOP/s)
headroom-v1: a lower bound from declared tensors and datasheet peaks. A kernel can sit well above it for good reasons.
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Implementation
Latency
vs #1
Trust
Observed
1321.8µs1.00×Reported · Apache-2.0 · source2026-06-06
Measured exactly what you asked. The source's designated baseline implementation. Reported by source; not independently reproduced.
source mirroredApache-2.0no install recipeView source →Run detail →
Implementations
Implementation
Runtime
Best latency
Evidence
Availability
group_gemm_mxfp4_flashinfer_g4_n4096_k2048FlashInfer-Bench baselines
python
321.8µs
1.00×
Reported
Apache-2.0 · source
Semantics
Inputs and outputs
a_fp8fp8_e4m3 [m, k]
a_scaleint8 [m, k_blocks]
b_fp4int8 [g, n, k_half]
b_scaleint8 [g, n, k_blocks]
m_indptrint32 [gp1]
cbf16 [m, n]
Axes and behavior
gconstant = 4
kconstant = 2048
mvariable
nconstant = 4096
gp1constant = 5
k_halfconstant = 1024
k_blocksconstant = 64
determinismunspecified
constraintsNo mutation or aliasing
Identity
aliasgrouped_gemm_mxfp8_mxfp4_g4_n4096_k2048sha256ab864a375e7a…
Sources: FlashInfer-Bench (2026-06-06) · Apache-2.0last observed 2026-06-06How records are decidedJSON