Stockfish compilation optimisation tool
It's a genetic algorithm that selects compiler flags ; here are the results versus the standard build :
| Engine | Nodes/second |
|---|---|
| stockfish_gene | 2296180.0 +- 17787.26 |
| stockfish_base | 2240525.0 +- 8060.88 |
Differences : 48329.0 +- 11991.0 Variance of the mean : 3461.5 ( 7.16 %) Speed up : 2.16 %
For the curious, here is the log of the 10 hour long genetic algorithm searching :
| gen | nevals | avg | std | min | max |
|---|---|---|---|---|---|
| 0 | 80 | 2.1427e+06 | 61942.9 | 1.98496e+06 | 2.25507e+06 |
| 1 | 48 | 2.18633e+06 | 39955 | 2.07916e+06 | 2.27133e+06 |
| 2 | 39 | 2.21791e+06 | 28757 | 2.13467e+06 | 2.2868e+06 |
| 3 | 67 | 2.22677e+06 | 26266 | 2.16215e+06 | 2.29096e+06 |
| 4 | 52 | 2.24399e+06 | 25810.4 | 2.11052e+06 | 2.30564e+06 |
| 5 | 46 | 2.25497e+06 | 22220.2 | 2.18655e+06 | 2.3173e+06 |
| 6 | 37 | 2.26564e+06 | 21046.1 | 2.19608e+06 | 2.3173e+06 |
| 7 | 46 | 2.26501e+06 | 23533.6 | 2.19704e+06 | 2.3173e+06 |
| 8 | 44 | 2.26582e+06 | 25033.4 | 2.16494e+06 | 2.3173e+06 |
| 9 | 43 | 2.26658e+06 | 31425.1 | 2.07488e+06 | 2.29723e+06 |
| 10 | 51 | 2.25534e+06 | 41331.3 | 2.03713e+06 | 2.31305e+06 |
| 11 | 52 | 2.24033e+06 | 53506 | 2.01191e+06 | 2.31624e+06 |
| 12 | 58 | 2.25418e+06 | 28526.7 | 2.16867e+06 | 2.31624e+06 |
| 13 | 49 | 2.25808e+06 | 27323.6 | 2.16867e+06 | 2.32158e+06 |
| 14 | 53 | 2.25222e+06 | 41972.4 | 2.05374e+06 | 2.32158e+06 |
| 15 | 41 | 2.26364e+06 | 37065.6 | 2.09473e+06 | 2.32801e+06 |
| 16 | 53 | 2.24563e+06 | 66500.9 | 1.97098e+06 | 2.32801e+06 |
| 17 | 46 | 2.27418e+06 | 37863 | 2.07659e+06 | 2.32801e+06 |
| 18 | 48 | 2.25872e+06 | 57503.1 | 1.98183e+06 | 2.32801e+06 |
| 19 | 49 | 2.25597e+06 | 60615.1 | 2.0529e+06 | 2.32801e+06 |
| 20 | 52 | 2.24536e+06 | 65997.5 | 2.0396e+06 | 2.32801e+06 |
| 21 | 44 | 2.26852e+06 | 39503.7 | 2.08433e+06 | 2.33017e+06 |
| 22 | 53 | 2.25146e+06 | 53316.9 | 2.10876e+06 | 2.33017e+06 |
| 23 | 47 | 2.26317e+06 | 35696.7 | 2.12476e+06 | 2.33017e+06 |
| 24 | 39 | 2.24376e+06 | 72410.6 | 2.01836e+06 | 2.33017e+06 |
| 25 | 49 | 2.28877e+06 | 24930.5 | 2.20957e+06 | 2.33124e+06 |
| 26 | 47 | 2.28984e+06 | 19162.4 | 2.2057e+06 | 2.33124e+06 |
| 27 | 37 | 2.29416e+06 | 21662 | 2.23704e+06 | 2.33124e+06 |
| 28 | 49 | 2.27985e+06 | 41746 | 2.13196e+06 | 2.33448e+06 |
| 29 | 47 | 2.29446e+06 | 23827 | 2.21151e+06 | 2.33448e+06 |
| 30 | 47 | 2.27739e+06 | 50384.3 | 2.09212e+06 | 2.33448e+06 |
| 31 | 47 | 2.28591e+06 | 45503.5 | 2.08778e+06 | 2.33448e+06 |
| 32 | 42 | 2.2932e+06 | 36403.5 | 2.19608e+06 | 2.33448e+06 |
| 33 | 44 | 2.29355e+06 | 38319.5 | 2.14193e+06 | 2.33448e+06 |
| 34 | 53 | 2.29241e+06 | 30277.6 | 2.15476e+06 | 2.33448e+06 |
| 35 | 43 | 2.29278e+06 | 40626.2 | 2.12566e+06 | 2.33448e+06 |
| 36 | 57 | 2.2953e+06 | 24803.9 | 2.20473e+06 | 2.33448e+06 |
| 37 | 49 | 2.26904e+06 | 64312.2 | 2.07574e+06 | 2.33448e+06 |
| 38 | 53 | 2.28056e+06 | 44706.6 | 2.11851e+06 | 2.33448e+06 |
| 39 | 42 | 2.28306e+06 | 47772.4 | 2.02811e+06 | 2.33448e+06 |
| 40 | 46 | 2.28564e+06 | 42651.1 | 2.06722e+06 | 2.33448e+06 |
Also, here are the optimisation flags found (in addition to -O3), all done with gcc 7.2.0, on an Intel 6700 processor :
-fmodulo-sched -fmodulo-sched-allow-regmoves -fgcse-lm -fgcse-sm -faggressive-loop-optimizations -fdeclone-ctor-dtor -fdevirtualize-speculatively -fdevirtualize-at-ltrans -flifetime-dse=2 -flive-range-shrinkage -fira-region=one -fira-loop-pressure -fno-ira-share-save-slots -fsched-pressure -fsched-spec-load -fsched-spec-load-dangerous -fsched-stalled-insns-dep=0 -freschedule-modulo-scheduled-loops -fipa-pta -fgraphite-identity -floop-nest-optimize -ftree-loop-vectorize -fvect-cost-model=cheap -fsimd-cost-model=dynamic -flimit-function-alignment -fweb -flto -flto-partition=max -ffast-math -funsafe-math-optimizations -fsplit-loops -fbranch-target-load-optimize2 -fbtr-bb-exclusive
There is still room for progress (no PGO for now), and I plan to add command line options to the tool.