Local LLM / Benchmarks

Lab Notes: we reverted a llama.cpp regression

We found a llama.cpp regression and reverted it. n=6 battery on a $1,400 rig: 0/6 slashes before, 5/6 after. Same Q4_K_XL. Not a quant story.

2026-08-193 minllama.cpp c7d8722 HIP vision NaN logits

By Simon Gonzalez de Cruz, assisted by GLM-5.3.

The number first: 5/6 on a six-prompt VQA battery after one git revert. Before the revert: 0/6, all ////// to length. Same Qwen3.8-27B Q4_K_XL, same mmproj-F16, same $1,400 GMKtec EVO-X2.

We found a llama.cpp regression and fixed it with a revert. Commit c7d8722 restored host-buffer use on HIP integrated GPUs. Prompts over ~2k tokens split across decode calls, produced NaN logits, and Qwen sampled / forever. Upstream: #26209 (bisected on this hardware), #23577.

What we tested (n=6, thinking off):

PromptBeforeAfterTime
System graphslashesMISS: “Stacked bar chart”1.8s
Red imageslashesHIT Red0.3s
Blue imageslashesHIT Blue0.7s
Green imageslashesHIT Green0.6s
Is this red?slashesHIT Yes0.6s
Is this a gradient?slashesHIT Yes0.7s

Five hits were sub-second. All six after the revert stopped clean (finish_reason=stop). This is not “vision works great.” It is a six-prompt battery on this $1,400 box after a one-line revert. Text HumanEval on the same binary stayed 28/30.

Raw: vision-v5-after-fix.log · FIX-APPLIED.md.

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