KernelBench cuda · H100

MegaQwen Decode Muse Spark 1.3

manually audited: clean

Isolated sequential regrade 0.0585 on a quiet H100 SXM 2026-09-03 16:41Z (in-run contended 0.0583, agent self-measured 0.0578). Third attempt on this box: the first two died on the 900 s muse idle timeout during long nvcc builds and are not archived; this one ran 08:38-16:30Z (7.9 h) with the idle limit at 3600 s and stopped on its own with a closing summary, harness exit 0. Fully authored CUDA via load_inline for sm_90: seven sync-free kernels per layer (fused RMSNorm plus QKV GEMV, q/k norm plus RoPE plus KV store, split-chunk attention scores / context / merge, O GEMV, gate plus up GEMV, SwiGLU plus down plus residual). No cuBLAS, no tensor cores; every projection is a hand-written split-K GEMV streaming bf16 weights through 128-bit __ldg with fp32 accumulate, bf16 rounded at the reference's points. One CUDA graph per decode step; the host updates a 16-byte StepP{pos, noise_ptr} struct and replays, so every timed step runs the full 4-layer computation over the whole KV cache with no window or early exit. Prefill is real and untimed (72.4 s at ctx 131072 in the regrade). check.py PASS at 3 seeds x {128, 256, 512} plus the 8192 spot; the agent also diffed 8192 and 32768 against the eager reference itself (worst max-abs 0.093750, one bf16 ulp at that magnitude) and claims a 131072 pass from its own script, which the harness never reproduces. The only keyed state is the captured graph, keyed on weight and cache data_ptrs, and replay reads the live buffers: probe on the quiet GPU gives cos(s1,s1b)=0.0921 for a new seed and cos(s1,s2)=0.0263 after an in-place weight overwrite, both with cos(ref,sol)=1.0000. Per-step noise is regenerated each call, unlike the RTX cell's (n, seed) cache. bwrap held: the hidden paths appear only as argv in the agent's own ps output; no export PATH, no clock commands, pip absent so nothing was installed, network only to the invited MegaQwen clone, template_mutated=false and template_files byte-identical. The agent caught a false PASS through the torch fallback during a broken build and paired every later PASS with a build assertion. A regeneration of this model's RTX cell, not a copy: different kernel decomposition, no library GEMM, one per-step graph instead of per-(pos, steps) graph keys.

20260903_083843_muse_muse-spark-1.3_03_megaqwen_decode