Author: Vincent Diepeveen
Date: 07:53:22 09/05/02
Go up one level in this thread
On September 04, 2002 at 14:29:05, Robert Hyatt wrote: you get even with fast memory on your quad only a 2.8 speedup on average at 30 positions. that's a lot more than a run on 1 position. >On September 04, 2002 at 14:02:54, Vincent Diepeveen wrote: > >>On September 04, 2002 at 12:43:37, Robert Hyatt wrote: >> >>Please run crafty at 16 processors. Fine with me. >>Even though it's a different program. I have no problems >>with it. > >And what would be the point? I might give you some 16 processor >numbers on a NUMA machine before long. I _might_. > > >> >>But rewrite also the article then that it's not a DTS thing, >>but a smp_lock thing that doesn't scale above 8 cpu's. > > >Vincent, the smp_lock thing doesn't hurt me thru 16 cpus as I already >know. I don't understand why you don't follow this, but in a typical >3 minute search, I see numbers like this: > > time=3:29 cpu=399% mat=0 n=303284136 fh=89% nps=1450k > ext-> chk=4663926 cap=1175890 pp=230533 1rep=74539 mate=3299 > predicted=2 nodes=303284136 evals=99342268 > endgame tablebase-> probes done=0 successful=0 > SMP-> split=774 stop=133 data=14/64 cpu=13:55 elap=3:29 > >That is from a real game played on ICC. > >Note it only did 774 splits. that is 774 smp_locks. Do you _really_ think >that hurts performance? _really_? > >If so, I have this bridge I need to get rid of... > >You can say smp_lock is a problem all you want. You can say that it killed >you on a NUMA machine all you want. But that doesn't mean it kills _me_ >on 8 or 16 processors... > > >BTW I would hate to publish 16 cpu crafty numbers, because that would probably >give you _another_ problem to overcome with your "sponsors". :)
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