Dev Builds » 20260825-1637

You are viewing an old NCM Stockfish dev build test. You may find the most recent dev build tests using Stockfish 15 as the baseline here.

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NCM plays each Stockfish dev build 20,000 times against Stockfish 14. This yields an approximate Elo difference and establishes confidence in the strength of the dev builds.

Summary

Host Duration Avg Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo

Test Detail

ID Host Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo CLI PGN

Commit

Commit ID 7ab49b9bda97a608e500762c1fd1d1c5857936f0
Author Joost VandeVondele
Date 2026-08-25 16:37:41 UTC
Use mmap() for large aligned allocations to avoid cross-NUMA arena reuse Worker/SharedHistories allocations on Linux were served by glibc malloc arenas, which survive thread destruction and can be reused by threads bound to a different NUMA node. This caused non-deterministic remote memory and lower NPS when Threads was set multiple times. Route aligned_large_pages_alloc_with_hint() through direct mmap() on Linux, storing the base/size so aligned_large_pages_free() can munmap() the original mapping. Merge the existing x86_64 MAP_HUGETLB bookkeeping into the same registry. fixes https://github.com/official-stockfish/Stockfish/issues/6516 Benchmark: 288 threads, 36864 MB hash, depth 15 (10 runs per config) ``` | Build | Case | Avg NPS | Min NPS | Max NPS | Range | |--------|--------------------------|-------------|-------------|-------------|-----------| | master | Case1 (Threads set x2) | 253,196,264 | 252,034,443 | 254,396,860 | 2,362,417 | | master | Case2 (Threads set x1) | 248,224,546 | 247,304,918 | 249,306,273 | 2,001,355 | | fix | Case1 (Threads set x2) | 254,675,607 | 253,991,054 | 255,600,403 | 1,609,349 | | fix | Case2 (Threads set x1) | 254,931,057 | 253,979,373 | 256,334,683 | 2,355,310 | ``` closes https://github.com/official-stockfish/Stockfish/pull/7095 No functional change
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