vLLM cuts Flint's kernels from 22 to 7 per MoE layer with custom fusion

vllm_project · x · 2026-10-22

The vLLM project collaborated with Recursive to make Flint fast from day one: custom kernels and aggressive operator fusion reduce kernel launches from 22 to just 7 per MoE layer at batch 1. The shared diagram details the fused path — attention side: Add+RMSNorm, QKV GEMV (fusing Q/K norm, RoPE, KV-cache write), decode attention with sinks and split-KV merge, and Output GEMV; MoE side: Add+RMSNorm with router top-6, Gate/up GEMV with shared expert and SiLU, Down GEMV with weighted combine. Runs NVFP4 at up to 8 requests; dense layers 0-1 replace the MoE row with a norm and two GEMVs.

Related event: Recursive releases Flint, an open-weights 40B MoE coding model built in under 4 months by its automated Eureka research system(50 posts)→

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