Author: Eugene Nalimov
Date: 10:48:49 12/09/03
Go up one level in this thread
On December 09, 2003 at 13:30:11, Slater Wold wrote: >On December 09, 2003 at 13:17:55, Robert Hyatt wrote: > >>On December 09, 2003 at 13:04:01, Slater Wold wrote: >> >>>On December 09, 2003 at 12:49:17, Robert Hyatt wrote: >>> >>>>On December 09, 2003 at 12:33:20, Slater Wold wrote: >>>> >>>>>On December 09, 2003 at 11:49:19, Mathieu Pagé wrote: >>>>> >>>>>>On December 09, 2003 at 11:16:02, stuart taylor wrote: >>>>>> >>>>>>>Is 2.2 Ghz. of a 64-bit computer a similar speed for chess as is 4.4 is it were >>>>>>>a 32-bit one? >>>>>>>If not, what? >>>>>>>S.Taylor >>>>>> >>>>>>Hi! >>>>>> >>>>>>No, it is not. >>>>>> >>>>>>64-bit computer are not twice as fast as 32-bit ones. The number of bit >>>>>>represent the natural lenght of an number on a cpu. Since chess engines use lot >>>>>>of 64 bits numbers they will run faster on 64 bits machines because on 32-bit >>>>>>machines they have to do some trick to do 64 bits maths that are natural on a 64 >>>>>>bit cpu. >>>>>> >>>>>>I dont think the improvement will be in the range of 2x speed up. Anyway it will >>>>>>vary from diffrents engines. >>>>>> >>>>>>Mathieu >>>>> >>>>>GCP reported 70% with Sjeng. >>>>> >>>>>Bob has reported about 50% with Crafty. >>>> >>>>Not exactly. I reported 1.0M with a 2.8ghz xeon, vs 1.6M with a 1.8ghz >>>>opteron. If you factor in a clock speed equalization, the xeon slows to >>>>1.8ghz and would produce about 650K nodes per second and the opteron would >>>>be more than 2x faster. >>>> >>>>I have not done a direct comparison of 32 bit code vs 64 bit code on the >>>>opteron as I have no 32 bit compiler available there. If I get to do that >>>>at some point it time, it would be interesting. It would be more interesting >>>>to be able to say "use only 32 bit ops, but use all 16 registers" to get a >>>>_real_ feel for what 64 bits offers over 32 bits, but that looks even >>>>harder to test. >>> >>>Well, we can always deduct. :) >>> >>>An opteron 144 (1.8Ghz) running SuSe and gcc33, using -m32 to produce 32 bit >>>code, got these results on 186.crafty: >> >>We can't compare with that at all. That is a _way_ old version, obviously. >> >>I can't do -m32 on this machine, as the libraries are all -m64 and they >>become incompatible (I have already tried this a few days back in fact.) >> >> >>> >>>90.1 1109 >>> >>>The fastest 2.8Ghz Xeon on SPEC's website does: >>> >>>92.0 1087 (2k AS IC++ 7.0 compiler) >>> >>> >>>For all practical purposes, we can say that a O144 a P4 2.8Ghz Xeon are >>>'comparible'. >> >>OK. Can't argue there with no data of my own to rely on.. >> >> >> >>> >>>1.0M to 1.6M = 60% speedup >> >>Not directly attributable to 64 bit however. -m32 restricts you to 8 >>registers, while -m64 adds the other 8. That also factors in and makes >>this less clear. > >Like I said, it was just a 'deduction'. I know you're pretty scientific, but >this was just a rough comparison. > >I'd be confident in this statement however: "64-bits, depending on application, >can speedup a typical chess program from 40% to 70%." > >Which is nice, considering it is practically 'free'. I am not so sure. Please take a look at one of the recent Opteron SPEC admissions: http://www.spec.org/cpu2000/results/res2003q4/cpu2000-20030922-02519.html. 3 out of 12 programs (1/4 of all programs) were compiled with "-m32" flag, because they are faster in 32-bit mode. Thanks, Eugene
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