Dev Builds » 20260402-1832

Use this dev build

NCM plays each Stockfish dev build 20,000 times against Stockfish 15. 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
ncm-dbt-01 06:44:10 582984 4000 1762 351 1887 +128.06 ± 4.5 0 33 550 1390 27 +295.94 ± 14.52
ncm-dbt-02 06:42:20 585418 4000 1736 357 1907 +124.89 ± 4.63 1 31 595 1334 39 +282.0 ± 13.93
ncm-dbt-03 06:42:22 584777 4000 1745 369 1886 +124.6 ± 4.52 0 29 596 1345 30 +283.58 ± 13.91
ncm-dbt-04 06:44:16 566557 4014 1754 374 1886 +124.52 ± 4.6 0 37 586 1351 33 +282.41 ± 14.06
ncm-dbt-05 06:43:38 581239 3986 1702 367 1917 +121.03 ± 4.6 1 36 609 1321 26 +273.8 ± 13.77
20000 8699 1818 9483 +124.62 ± 2.04 2 166 2936 6741 155 +283.45 ± 6.27

Test Detail

ID Host Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo CLI PGN
464128 ncm-dbt-04 565548 14 7 2 5 +129.72 ± 68.06 0 0 2 5 0 +311.09 ± 530.6
464127 ncm-dbt-05 581485 486 200 49 237 +111.64 ± 12.72 0 4 85 153 1 +250.36 ± 36.91
464126 ncm-dbt-02 586816 500 209 37 254 +124.6 ± 12.53 0 3 75 169 3 +285.49 ± 39.5
464125 ncm-dbt-01 584076 500 222 42 236 +130.94 ± 11.96 0 2 68 178 2 +309.64 ± 41.56
464124 ncm-dbt-03 584706 500 212 49 239 +117.55 ± 13.7 0 10 69 169 2 +265.78 ± 41.36
464123 ncm-dbt-04 566257 500 213 50 237 +117.55 ± 13.87 0 10 70 167 3 +263.42 ± 41.06
464122 ncm-dbt-05 583028 500 217 36 247 +131.74 ± 13.3 0 6 62 177 5 +304.07 ± 43.81
464121 ncm-dbt-02 584034 500 226 49 225 +128.55 ± 13.19 0 3 74 166 7 +288.06 ± 39.79
464120 ncm-dbt-01 580945 500 222 41 237 +131.74 ± 13.12 0 6 61 179 4 +306.84 ± 44.17
464119 ncm-dbt-03 583698 500 213 44 243 +122.24 ± 12.94 0 3 80 162 5 +273.0 ± 38.12
464118 ncm-dbt-04 565784 500 213 48 239 +119.11 ± 13.52 0 6 78 161 5 +263.42 ± 38.85
464117 ncm-dbt-05 580489 500 212 48 240 +118.33 ± 13.17 0 4 83 158 5 +261.07 ± 37.44
464116 ncm-dbt-02 584664 500 224 43 233 +131.74 ± 12.54 0 2 70 173 5 +304.07 ± 40.91
464115 ncm-dbt-01 583614 500 221 47 232 +126.17 ± 13.24 0 5 71 169 5 +285.49 ± 40.81
464114 ncm-dbt-03 586646 500 224 47 229 +128.55 ± 13.19 0 5 68 172 5 +293.29 ± 41.75
464113 ncm-dbt-04 565587 500 214 49 237 +119.11 ± 13.17 0 4 82 159 5 +263.42 ± 37.69
464112 ncm-dbt-05 582819 500 213 45 242 +121.45 ± 13.31 0 6 74 166 4 +273.0 ± 39.95
464111 ncm-dbt-02 586943 500 225 45 230 +130.94 ± 13.51 0 5 67 171 7 +295.94 ± 42.08
464110 ncm-dbt-01 584285 500 220 34 246 +135.76 ± 12.01 0 3 60 185 2 +327.18 ± 44.54
464109 ncm-dbt-03 584411 500 219 47 234 +124.6 ± 12.33 0 1 80 165 4 +282.94 ± 37.88
464108 ncm-dbt-04 565194 500 222 37 241 +134.95 ± 11.83 0 2 63 183 2 +324.17 ± 43.32
464107 ncm-dbt-02 585337 500 214 38 248 +127.76 ± 12.65 0 3 72 171 4 +293.29 ± 40.39
464106 ncm-dbt-05 582652 500 216 44 240 +124.6 ± 11.74 0 2 74 174 0 +293.29 ± 39.69
464105 ncm-dbt-03 584916 500 219 44 237 +126.97 ± 12.66 0 3 73 170 4 +290.66 ± 40.08
464104 ncm-dbt-01 582903 500 217 54 229 +117.55 ± 13.36 0 7 76 164 3 +263.42 ± 39.41
464103 ncm-dbt-04 568832 500 217 50 233 +120.67 ± 12.22 0 3 78 168 1 +277.93 ± 38.66
464102 ncm-dbt-02 586393 500 206 49 245 +112.91 ± 13.22 0 5 87 154 4 +247.41 ± 36.56
464101 ncm-dbt-05 579207 500 207 51 242 +112.14 ± 13.22 0 8 79 162 1 +251.89 ± 38.63
464100 ncm-dbt-03 582193 500 219 50 231 +122.24 ± 12.57 0 3 78 166 3 +277.93 ± 38.66
464099 ncm-dbt-01 584369 500 212 37 251 +126.97 ± 12.85 0 4 71 171 4 +290.66 ± 40.76
464098 ncm-dbt-04 567522 500 227 57 216 +123.02 ± 13.47 0 3 82 157 8 +268.17 ± 37.61
464097 ncm-dbt-02 584285 500 221 50 229 +123.81 ± 13.63 1 3 76 164 6 +277.93 ± 39.29
464096 ncm-dbt-05 579166 500 219 42 239 +128.55 ± 12.63 1 2 68 177 2 +304.07 ± 41.65
464095 ncm-dbt-03 584664 500 220 49 231 +123.81 ± 12.73 0 2 80 163 5 +277.93 ± 38.02
464094 ncm-dbt-04 566060 500 213 43 244 +123.02 ± 13.47 0 8 67 172 3 +280.42 ± 42.05
464093 ncm-dbt-01 582611 500 228 48 224 +130.94 ± 12.76 0 2 72 170 6 +298.62 ± 40.29
464092 ncm-dbt-02 584874 500 211 46 243 +119.11 ± 13.34 0 7 74 166 3 +268.17 ± 39.97
464091 ncm-dbt-05 581070 500 218 52 230 +119.89 ± 13.68 0 4 84 154 8 +258.75 ± 37.2
464090 ncm-dbt-03 586985 500 219 39 242 +130.94 ± 11.96 0 2 68 178 2 +309.64 ± 41.56
464089 ncm-dbt-04 568236 500 228 38 234 +138.99 ± 12.3 0 1 64 179 6 +327.18 ± 42.83
464088 ncm-dbt-01 581070 500 220 48 232 +124.6 ± 12.33 0 4 71 174 1 +290.66 ± 40.76

Commit

Commit ID c41c9bb9733be48b232afd042c9331dde9000e03
Author anematode
Date 2026-04-02 18:32:34 UTC
Add -fno-ipa-cp-clone on GCC Passed non-regression STC at tests.stockfishchess.org/tests/view/69c9b8c3a54395a761335044 (set to gainer bounds, *mea culpa*) There's a major performance penalty when compiling the fish with GCC 16. @Torom 's measurements (similar to mine, but more precise): ``` GCC 15 (master) vs. 16 (master) sf_base = 2549174 +/- 2984 (95%) sf_test = 2435456 +/- 2239 (95%) diff = -113718 +/- 3599 (95%) speedup = -4.46100% +/- 0.141% (95%) GCC 15 (master) vs. 16 (patch) sf_base = 2544107 +/- 3091 (95%) sf_test = 2568837 +/- 3164 (95%) diff = 24729 +/- 4359 (95%) speedup = 0.97204% +/- 0.171% (95%) ``` Based on looking at the disassembly + profiling data of the builds, the root cause appears to be overly aggressive code duplication from constant propagation of various functions especially in `search.cpp`. The worst offender is `Worker::search`, which I think is being cloned and optimized based on the value of `cutNode`. `perf stat` indicates that the instruction cache miss rate goes up by ~50% on the GCC 16 build. closes https://github.com/official-stockfish/Stockfish/pull/6691 No functional change
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