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Subject: Re: Some strange things about Crafty 1917

Author: Dann Corbit

Date: 14:40:51 09/17/04

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On September 17, 2004 at 17:09:04, Robert Hyatt wrote:

>On September 17, 2004 at 14:05:10, Dann Corbit wrote:
>
>>There is a memory leak somewhere (maybe in the tablebase code?)
>>After letting Crafty run all night analyzing WAC at 3 minutes per position with
>>494 megs ram allocated (14M tablebase, 384M hash, 96 pawn hash) Windows task
>>manager indicated a peak physical memory usage of 800MB and a virtual memory
>>size of 2,090,964K = 2GB.
>>
>>Crafty solved 299/300 on WAC, but some strange things surfaced.  The one problem
>>not solved was NOT one of the few difficult ones like WAC.230, WAC.141 but was
>>instead WAC.274.  Also, in the log file, we see a couple "captured a king"
>>messages.
>
>This indicates a serious problem.  Often caused by bugs as I am testing, but for
>released versions, most commonly they are caused by compiler optimizer bugs
>instead.
>
>19.17 has been running and has played several hundred games, plus a lot of long
>testing on the 4-way opteron before AMD zapped it to use for another project.
>In looking at all the log files, I _never_ see that error message...
>
>I tried wac274 and get Rg2 from ply 2 on, with the score climbing each
>iteration.  Something looks broken there...  IE what compiler version, options,
>etc??

It's a beta compiler, so quite likely, that is where the problem is coming from.
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 14.00.40607.16 for 80x86
Copyright (C) Microsoft Corporation.  All rights reserved.

These are the exact compiler flags:
/Ox /Og /Ob2 /Oi /Ot /Oy /GT /GL /I "c:\program files\Microsoft SDK\Include" /D
"NDEBUG" /D "WIN32" /D "_CONSOLE" /D "WINDOWS" /D "EGTB6" /D "NT_i386" /D "FAST"
/D "VC_INLINE_ASM"  /D "DETECTDRAW" /D "EPD" /D "USE_ASSEMBLY"  /D "_MBCS" /GF
/FD /MT /Zp16 /Gy /fp:fast /Fp"Release/crafty.pch" /Fo".\Release/"
/Fd".\Release/" /W4 /nologo /c /Gr

In debug mode, the position solves correctly, so it may be related to a bad
optimization.

The other positions all analyze fine (debug or release).



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