Upstream: TurboQuant discussion + contribution requirements for llama.cpp

Author: TheTomCreated Mar 25, 2026Updated May 4, 2026
Labelstype:portP2

Upstream llama.cpp Activity

Active discussions

Contribution requirements (PR #19762, merged Mar 13)

To upstream a new quant type, must provide:

  • GGUF conversion support
  • Perplexity vs FP16 comparison
  • KL divergence data
  • CPU performance baselines

Relevant optimizations to rebase on

  • PR #20962: Metal Tensor API — 26% mul_mat improvement
  • PR #20609: MXFP flash attention SoA layout pattern

Key lesson from upstream

Custom quant types that aren't in Metal SET_ROWS whitelist silently fall back to CPU. We hit this bug. Pattern confirmed by MXFP4 experience (PR #20609).