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Subject: Re: IA-64 vs OOOE (attn Taylor, Hyatt)

Author: Robert Hyatt

Date: 21:49:18 02/20/03

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On February 20, 2003 at 20:10:58, Eugene Nalimov wrote:

>On February 20, 2003 at 19:09:18, Tom Kerrigan wrote:
>
>>It seems you know a lot more than I do about instruction latencies. How do you
>>explain Crafty's disproportionate speedup on IA-64, then? And why would you
>>think Crafty's performance is a good predictor of other chess programs on IA-64
>>when Crafty is so much different from many other programs?
>>
>>Of course, all we have is Hyatt's word that Crafty does well on IA-64, although
>>he's never seen it in person, and people who have seen Crafty run on IA-64 in
>>person seem to contradict him...
>>
>>-Tom
>
>I saw Crafty on Itanium2 in person, and results were closer to what Bob reported
>here than to what was reported here recently.
>
>Thanks,
>Eugene


I have only seen _one_ bad Itanium2 report.  I have seen _two_ good reports,
one from Eugene, one from someone inside Intel.  I have a problem with the
Intel version because of the spec stuff I did and a NDA that is in force.

However, there are other good 64bit results from the alpha 264 chip as well,
factoring 800K from 600mhz would reach beyond 1600K at 1.25ghz, which is the
fastest 264 I have seen.

Eugene has never told me what he did to produce good results.  Nor do I know
what Intel did specifically as I was not really involved and it was just a
"heads up" from someone there about an interesting result.  Whether either
(Eugene or Intel) tweaked the code I don't know.  I specifically know that Tim
did not for the 600mhz 264 results I posted here, he compiled that code as is
and ran it, without even testing to see if compact-attacks was better than the
default or not.

I don't understande all the 64 bit nonsense myself.  It seems pretty obvious
that for 64 bit operations, they are going to be faster, _period_.  For 32 bit
programs, who cares?  Sort of like benchmarking a non-vector program on a Cray.
Of course it will not run very well.



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