Author: Robert Hyatt
Date: 06:32:00 06/18/98
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On June 18, 1998 at 08:06:32, Michael Kalisz wrote: >Hello everyone > >This question is for all of you who run crafty on SMP machines: > >I've compiled crafty on 2 CPU machine running HP-UX 11.00 >(crafty-15.12, opt= -DSMP -DCPUS=2 -DMUTEX -DPOSIX) > >But I usely get better performance when running on one CPU >then on two. (When using the bench command) > >So how much performance improvment should I expect when running >crafty on 2 CPU machine comparing to one?? you should see results about 1.5-1.75X faster. The problem is likely the -DMUTEX, because MUTEX locks are *very* inefficient. You need to find a way to implement spinlocks on your machine, as I did on the X86, and as others did for the alpha. Crafty does some *very* fine-grained parallel searching, and if the "locks" are inefficient, it will not work well. > >Would carfty benefit even more when running on 4 or 8 processors? > >Do I need to set the mt,mtmin,mtmax to some special values?? >(I've now set mt=2) those are tunable parameters, although for me, the defaults work best. First thing to do is solve the lock problem... > >Thanks in advance > >Michael
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