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Subject: Re: Crafty SMP problem

Author: Robert Hyatt

Date: 09:06:40 01/24/01

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On January 24, 2001 at 10:22:28, Bernhard Bauer wrote:

>On January 24, 2001 at 06:51:30, David Rasmussen wrote:
>
>>I have a problem with Crafty.
>>
>>I'm trying to run it on a solaris system with 24 CPUs (I've tried it as well on
>>a 12 CPU machine of the same kind).
>>
>>I sometimes get the message "ERROR.  no SMP block can be allocated".
>>What does this mean? What is the problem
>
>In chess.h is a line
>#define MAX_BLOCKS    16*CPUS
>
>You may change this line to a greater value.
>For CPUS=2 this did noz work for me, so I use
>#define MAX_BLOCKS    128
>and that works.
>
>Kind regards
>Bernhard


When you say "did not work for me" do you mean you got the out of blocks
error?  2*16 should work for a dual.  4*16 works for my quad and never
produces an error.  If you watch the SMP part of the statistics output, it
shows the max number of blocks used during a search:

              SMP->  split=507  stop=83  data=17/64  cpu=22.77  elap=6.18

in my case, 17 blocks was the peak usage, with a total of 64 (4*16).  I would
definitely be interested to know your peak number for a dual system.  I would
expect something in the 8-10 range typically.  On my quad it averages about 12
over the course of a game.




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