Author: Vincent Diepeveen
Date: 16:20:35 09/03/01
Go up one level in this thread
On September 03, 2001 at 12:23:53, Robert Hyatt wrote: >On September 03, 2001 at 12:06:26, Vincent Diepeveen wrote: > >>On September 02, 2001 at 17:26:31, Tom Kerrigan wrote: >> >>>On September 01, 2001 at 08:40:46, Vincent Diepeveen wrote: >>[snip] >> >>>>completely (especially price range), as well from the >>>>servers from alpha and especially from SUN and all other cpu >>>>brands when running 32 bits (computerchess) software, >>> >>>Seems like lots of computer chess programs are 64 bit now, and the Alpha can >>>more than hold its own against any PC processor running either 32 or 64 bit >>>code. >> >>This is what i mean, an alpha 2 processor is around $20000 in the >>store now. that's for a 833Mhz dual alpha. >> >>A dual 1.2Ghz K7 of course blows that away for DIEP. >> >>An alpha 633Mhz (21164) used to be for diep around the same >>speed like a PII at 380Mhz. >> >>And the PII was 17.3% faster than a PII >>the K7 is another 10% faster than a P3 >>the palomino i have now is another few % faster. >> >>21264 has about the same number of registers as a K7, >>and the 21264 has huge costs for branch mispredictions. >>The 4 instructions a clock it sometimes can do hardly make up >>for the lack of 400Mhz in speed. >> >>And that for a factor of 10 in price difference... >> >>>-Tom > > >Your numbers are simply wrong. You are using a poorly behaved program, >written to work well in a 32 bit machine, to judge a 64 bit cpu. The 21264 >for crafty will rip the cover off of any PIII/PIV you care to drag up, even >though the alpha isn't running anywhere near the same clock rate. Of course i'm having a program which is not made for a 64 bits machine, that's pretty logical. Note that crafty's numbers at the Sun aren't too great, though this IS a 64 bits machine. DIEP at a sun is more than OK (considering its Mhz). >Your program would also die on a Cray, because you haven't given any thought >in how to use a Cray's unique features. But that doesn't mean _everybody_ is This is simply dead wrong, please tell me where new cray machines are getting build. Isn't the company bankrupt or something? AFAIK all crays build now use alpha processors, also a horse i wouldn't bet on too long. So should i rewrite diep for a cray? >in the same boat on 64 bit machines. And once you start to use the features >they offer, the performance gains are impressive. >The old saying "garbage in garbage out" still holds. You have to have a program >that is designed for the architecture. Feel free to write crafty in VERILOG or whatever, and when you have pressed a cpu, come back and then we'll play with the latest diep version against your old crafty version which took so long to translate. Nah that's pretty mean from me to say. To rewrite a program to a very specific machine which focuses upon bandwidth, because let's not forget that Crays are made for bandwidth, NOT with computerchess in mind, it takes years to translate a couple of megabytes of C code to Cray assembly! That's not only a waste of time, but also a very dumb thing to do. At the time you have rewritten it, your program is outdated! OUTDATED!
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