Author: Mike Byrne
Date: 21:21:05 05/20/02
Go up one level in this thread
On May 20, 2002 at 12:01:32, Robert Hyatt wrote: >On May 19, 2002 at 18:05:36, Mike Byrne wrote: > >>I have been away from computer chess for a while and was glad there is still a >>large interest in computerchess. Many thanks to those who wrote the "Arena" >>software -- it's nice work and has room for many more improvements. >> >>It is good to see Crafty is alive and well - the latest version 18.14 is very >>solid. I am able to get 1,000,000 nodes per second using MVC++ 6.0 and the >>Intel "plug in" compiler. However my intel license is the of the demo variety >>and will expire in 30 days or so. The intel compiler does have a nifty option >>that uses the >>a Profile-guided Optimizations - here's a brief overview: > > >You overlooked a _key_ issue. If you are using the compiler non-commercially, >then you can get a permanent license at no cost. I am using it on my Linux box >in fact... > >They only charge if you are using it to develop/distribute commercial software. > Thanks for the info, Bob - I saw your note and sent an email to Intel write away - it would be nice if they send me a non expiring license. Back to tinkering with Crafty - NOT sure if it plays better after my "changes" - but it sure is fun! Rignt now playing a 100 game blitz match vs YACE at TC 2 3. After 21 games - modified Crafty is up 12.5-8.5. >> >>" >>Profile-guided optimizations (PGO) tell the compiler which areas of an >>application are most frequently executed. By knowing these areas, the compiler >>is able to be more selective in optimizing the application. For example, the use >>of PGO often enables the compiler to make better decisions about function >>inlining, thereby increasing the effectiveness of interprocedural optimizations. >> >>Instrumented Program >>Profile-guided optimization creates an instrumented program from your source >>code and special code from the compiler. Each time this instrumented code is >>executed, the instrumented program generates a dynamic information file. When >>you compile a second time, the dynamic information files are merged into a >>summary file. Using the profile information in this file, the compiler attempts >>to optimize the execution of the most heavily travelled paths in the program. >> >>Unlike other optimizations, such as those used strictly for size or speed, the >>results of IPO and PGO vary. This is due to each program having a different >>profile and different opportunities for optimizations. The guidelines provided >>here help you determine if you can benefit by using IPO and PGO. >> >>In this version of the Intel® C++ Compiler, PGO is improved in the following >>ways: >> >>Register allocation uses the profile information to optimize the location of >>spill code. >> >>For indirect function calls, branch prediction is improved by identifying the >>most likely targets. With the Pentium® 4 processor's longer pipeline, improved >>branch prediction translates to higher performance gains. >> >>The compiler detects and does not vectorize loops that execute only a small >>number of iterations, reducing the run time overhead that vectorization might >>otherwise add. >>" >> >> >>My fastest compiler options using the Intel were as follows: >> >>CFLAGS = /G7 /Gr /O3 /Ob2 /Ot /Oi /Oa /GA /Zm200 /QxW /Qip /Qprof_gen >> >>G7 & QxW is for Pentium 4, /03 is an aggressive use of optimazitions, >> >>You must then run the program and play a few games then repeat the compliation >>process using >> >>CFLAGS = /G7 /Gr /O3 /Ob2 /Ot /Oi /Oa /GA /Zm200 /QxW /Qip /Qprof_use >> >>I gained roughly 10% more nodes with the Intel compiler over MSVC 6- although I >>have heard Visual.net is also faster than MSVC 6. >> >>There are now multiple hundreds of free chess programsthat run the winboard or >>UCI protocols - that is also very good for computer chessn enthusiasts. >> >>Later this year - Pocket Pc's will be running 400 Mhz CPU's - that will make for >>very a solid portable chess machine. >> >>Best wishes to all. >> >>Mike Byrne
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