B-3 (the 0017-deferred mmq_y-down warp-remap of the NVFP4 grouped FP4-MMA
mul_mat_q) was built bit-exact on the clean 0025 base and measured: the
grouped GEMM kernel itself runs -1.3% (occupancy did rise via the nwarps=4
warp-remap / 128 threads-per-CTA), but end-to-end MoE decode is FLAT
(npl128 +0.4%, npl32 +0.3%, within noise) because the stream-k fixup grows
+42% (mmq_y=64 doubles the row-tiles) and the step is SSM/BW-bound. md5 PASS
both models, test-backend-ops MUL_MAT 1146/1146 + MUL_MAT_ID 806/806 PASS.
No patch 0028; DGX dev tree reverted to pristine 0025.
Assessment: the bit-exact MoE GEMM/launch track is exhausted (B-1 re-graph
banked ~82->85%; B-2 and B-3 are 0). Honest bit-exact MoE ceiling = ~85% of
vLLM @npl128. The residual is the structural Marlin-NvFp4 grouped-GEMM gap
that no bit-exact lever closes. Recommend shipping the ~85% bit-exact default
and exposing the held 0026 bf16-SSM as a default-off opt-in (it reaches ~95%
but is non-bit-exact and fails the MoE KL gate).
Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
9c1c2a6a16
