llama.cpp NUMA mirroring boosts dual-EPYC inference by up to 137%

mattescala · reddit · 2026-08-30

Addressing the dual-socket bottleneck where cores read weights across the slow interconnect, the author enabled the unused NUMAMIRROR strategy in ggml-cpu.h. This keeps a full copy of weights on each NUMA node, doubling RAM usage but allowing local access. Benchmarks show 64-71% speedups for DeepSeek-V4 and GLM-5.2, and a massive 137% boost for gemma-4-31B dense decoding. A PR has been submitted to llama.cpp.

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