Author: Russell Reagan
Date: 17:54:24 06/23/04
Go up one level in this thread
On June 23, 2004 at 19:52:45, Ed Trice wrote: >If you profile Crafty, you will find something like only 11% of the computation >is spent on the evaluation routine. Say you were to make this code execute twice >as fast. Then, overall, the entire program would be only 5.5% faster. > >To make a big performance gain, you have to attack the bottlenecks. I agree with that logic. At the same time, I think it should come with a warning. A lot of times people mistakenly interpret this advice as, "ignore optimization until the program is operational." I think that by doing that, you are placing the upper limit on how fast the program can potentially be much lower than it should be. Let's say I write my program, and I ignore optimization issues early on. The program is now operational, and now I start to work on optimizations. I profile it, hunt down hot spots, and get to the point where there are no obvious bottlenecks. The program is still ten times slower than Crafty. Now what? I am saddled with a poor overall design, and nothing short of a complete rewrite is going to improve the situation. I also have to disagree with that number, 11%. I just compiled it and ran it through a profiler. Here are the top 20 consumers. Evaluation totals almost 50% of the execution time. However, your point is well taken. Spending a significant amount of time improving MakeMove() and UnmakeMove() wouldn't gain much. Method Name % in Method % with Children Called Average Evaluate 22.2 45.9 84,623 6.6 EvaluatePawns 17.1 17.1 53,913 8 Search 7.4 90.9 34,386 5.4 GenerateCaptures 7.3 7.3 51,903 3.5 MakeMove 6.6 6.6 92,827 1.8 UnmakeMove 4.4 4.4 92,823 1.2 Attacked 4.1 4.1 144,934 0.7 Quiesce 3.7 61.2 84,623 1.1 NextMove 3.5 6.4 72,219 1.2 InitializeHashTables 3.1 3.1 5 15,640.10 EvaluateKingSafety 2.7 2.7 84,621 0.8 EvaluateDevelopmentW 1.7 1.7 84,623 0.5 Swap 1.7 3.4 34,061 1.2 HashProbe 1.6 1.6 34,390 1.2 EvaluateDevelopmentB 1.4 1.4 84,623 0.4 HashStore 1.3 1.3 28,957 1.1 Iterate 1.1 93.8 4 7,106.40 AttacksTo 1.1 1.1 36,998 0.7 InitializeZeroMasks 0.9 0.9 1 22,945.10 GenerateNonCaptures 0.9 0.9 2,786 7.7
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