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Subject: Re: Which programs make use of 2 or more processors?

Author: Robert Hyatt

Date: 10:48:04 06/22/99

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On June 22, 1999 at 12:11:26, James Swafford wrote:

>On June 22, 1999 at 05:43:15, Vincent Diepeveen wrote:
>
>>On June 22, 1999 at 02:27:32, Jouni Uski wrote:
>>
>>>On June 22, 1999 at 02:20:06, Mark Longridge wrote:
>>>
>>>>Does anyone know if there are any programs aside from crafty which
>>>>support more than 1 cpu? I'm interested in multi-cpu software,
>>>>both shareware and commercial.
>>>>
>>>>Thanks
>>>
>>>Fritz5.32 supports 2 prosessors under Windows NT. So You can run engine-engine
>>>with ponder!
>>>
>>>Jouni
>>
>>DIEP: n processors, where n is any number > 0.
>>email me: diep@xs4all.nl
>>
>>DIEP runs both under linux and NT.
>>
>>Speedup out of 4 processors at world championship was 4.0
>
>How do you get a speedup of 4.0 with 4 processors?
>Do you claim *no* loss?  For n processors, is the speedup
>always = n?
>
>I've heard others state that 3.2 or 3.3 is a good speedup
>for 4 processors....
>
>Please enlighten me.
>
>--
>James
>
>
>>
>>The parallellism in DIEP is an improved version of the Cray Blitz
>>parallellism.
>>
>>Many thanks to Hyatt for explaining me how to do parallellism and
>>giving me the opportunity to run and test at 4 processors!
>>
>>Greetings,
>>Vincent


Until his program is fully debugged, there is little point in speculating.

once it is, it is easy to do a full 10-ply search with 1 cpu, and then a
full 10-ply search with 4 cpus and see what happens.  Cray Blitz got fairly
close to 4 (I don't remember the exact numbers and am not at my office to
check the DTS article in JICCA).  Crafty is currently hitting 3.2-3.3 on an
average of several test suite positions....

I don't see how to hit 4.0 without perfect move ordering, or absolutely worst
-first move ordering.  Either of those is trivial to go 4.0x with, but with
the normal 90-95% right ordering we see, 4.0 is _very_ difficult...

At least for me...



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