Author: Vincent Diepeveen
Date: 10:24:22 06/05/02
Go up one level in this thread
On June 04, 2002 at 20:31:41, Robert Hyatt wrote: No one can buy such a 'common' alpha that gets 1 million nodes a second despite what you write. Only Tim who worked with DEC alpha in past times had one. So i don't see that as 'common'. The production alpha's all are benchmarked at specint and hell slower than IA32 processors are. >On June 04, 2002 at 18:01:03, Gian-Carlo Pascutto wrote: > >>On June 04, 2002 at 17:52:47, Dann Corbit wrote: >> >>>On June 04, 2002 at 16:28:39, Gian-Carlo Pascutto wrote: >>> >>>>On June 04, 2002 at 16:18:55, Gian-Carlo Pascutto wrote: >>>> >>>>>Because you are using a processor that is clocked at twice the clock >>>>>frequency? Why compare a 1ghz processor to a (nearly) 2ghz processor >>>>>and conclude anything about efficiency there? Is there anything that >>>>>suggests that the alpha is simply more "efficient"? To justify that >>>>>clock frequency disparity? >>>>> >>>>>A machine twice as fast (clock freq) _should_ perform just as well as >>>>>a 64 bit machine at 1/2 the frequency... Less would suggest that the >>>>>32 bit machine simply sucks badly. >>>> >>>>I don't agree with the validity of a clock-for-clock comparison, >>>>but if you want to do it anyway, I'll again point to Vincent's >>>>numbers: >>>> >>>>At the same clockspeed, Crafty only gets 33% faster on the 64-bits >>>>machine. >>>> >>>>When you read this, keep in mind that most applications get _more_ >>>>than 33% faster on the 64-bits machine. >>> >>>All the new 64 bit chips in the discussion are pretty much beta stage right >>>now. >> >>Not true for the Alpha. > >Depends on the alpha being discussed. DEC had processors beyond the 21264 >running. Although the 21264 was pretty good. Dann was a bit off on the >performance as Tim Mann was running a 21264 at 600mhz and getting right at >1M nodes per second. Mckinley is getting 1.5M at 1000mhz, so the alpha might >have a bit of an advantage still. but it is pretty small... > >Mckinley is only available to a select few. 21264's are fairly common. >Anything beyond that is not readily available... > > >> >>>So, I think that architecturally, it makes good sense to design for a 64 bit >>>system right now. >> >>That makes sense, if the 64 bit design is actually faster than the corresponding >>32 bit design (even on 64 bit hardware if you wish). >> >>The case for bitboards is not clear on that matter. Certainly, if >>the speedup over nonbitboards is only 33% they will have a hard time >>convincingly beating alternative appraoches even on 64 bit hardware. >> >>-- >>GCP > >You are assuming that bitboards are _slower_ than non-bitboard programs on >32 bit machines. I haven't seen this demonstrated yet. We can always do some >sort of a test. IE since the most common move generator issue is "generate all >captures" we can try that with bitboard and non-bitboard approaches to see if >one is really much better than the other on 32 bit machines. I don't think so >myself. I think they are pretty equal due to the multiple pipe issue. > >But a test could be done to see, since this is the most common thing needed >in a chess engine.
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