Author: Rolf Tueschen
Date: 07:13:27 05/05/04
"Jan Selschotter - Heidi Wyffels" <j.NOselschotterSPAM> wrote: > "Robert Hyatt" <hyatt@crafty.cis.uab.edu> schreef in bericht > news:aks1th$ffv$2@juniper.cis.uab.edu... >> marco <vialospamm.ledro@tiscali.it> wrote: >> > Hi at all >> > I want change my PC.... >> > What is the Crafty SMP performance improvement compare to same processor >> > family/tipe ? ( for example in Kn/sec or in elo points ) >> > Is there a site with some data table ? >> > THX >> > Marco >> >> I am not sure what you are asking. If you mean "how much faster will >> crafty run on a dual processor at XXXXmhz per cpu than it will run on >> a single XXXXmhz cpu?" then the answer is about 1.7 times faster on >> average. Sometimes more, sometimes less... > And on N cpu's? Does speed(N)/speed(N-1) go to 1 for big N? I suspect so but there has been no way to test it so far. In a better SMP algorithm used in Cray Blitz, for 16 cpus the speedup had flattened to 11.1 from an optimal of 16.0. using 2 cpus it was very close to 2.0, close enough that rounding to 1 decimel place made it 2.0. So obviously the curve is hyperbolic and has an asymptote somewhere out there. And I doubt it gets to 32 for any number of processors... Crafty is not as efficient, so it might have a max of 16 or worse, since I have not tested it on a large SMP box (yet). For one thru four processors, crafty's SMP speedup is about speedup = 1 + .7 * (NCPUS -1) which gives about 3.1 for 4 cpus. Whether it will hold for 8 and 16 I don't know (yet). -- Robert Hyatt Computer and Information Sciences hyatt@cis.uab.edu University of Alabama at Birmingham (205) 934-2213 115A Campbell Hall, UAB Station (205) 934-5473 FAX Birmingham, AL 35294-1170
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