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Subject: Re: Quad scaling ?

Author: Vincent Diepeveen

Date: 07:32:52 08/25/05

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On August 24, 2005 at 12:27:11, Robert Hyatt wrote:

>On August 24, 2005 at 12:05:09, Vincent Diepeveen wrote:
>
>>On August 24, 2005 at 08:59:28, Thomas Logan wrote:
>>
>>>On August 24, 2005 at 08:47:33, Vincent Diepeveen wrote:
>>>
>>>>On August 24, 2005 at 08:20:25, Thomas Logan wrote:
>>>>
>>>>>Does anyone have scaling figures for various deep programs
>>>>>
>>>>>and systems with 2 dual core processors
>>>>>
>>>>>Tom
>>>>
>>>>hi, i just started a test at my k7 single cpu machine
>>>>to compare an output created at a quad dual core 1.8Ghz.
>>>>
>>>>The test is over 213 positiosn and statistical significant.
>>>>
>>>>I expect results within 2 weeks.
>>>>
>>>>You can calculate what time it takes 70 minutes * 213 positions.
>>>>
>>>>one thing already seems sure:
>>>>
>>>>x86-64 has no scaling problems with big hashtables, x86 has.
>>>>
>>>>Vincent
>>>
>>>Hello Vincent
>>>
>>>Thank you
>>>
>>>Are you using Diep ?
>>>
>>>Any knowledge concerning Fritz, Junior or Shredder
>>>Please post your results when obtained
>>
>>Shredder is scaling 3.3 at quad single core, so that'll be like scaling of 4 at
>>dual core quad or so?
>>
>>junior was single core and fritz will not be scaling well either (deepfritz8).
>>
>>We know all this already from 8 cpu Xeon machines in fact. See results donninger
>>posted once.
>>
>>If you don't run well at 8 cpu xeon then forget dual core.
>
>
>Not necessarily.  8cpu xeon was a kludge.  Has same memory bandwidth as a 4-cpu
>xeon.  Which means extra 4 cpus just cause a significant memory bottleneck.  I
>ran on one of these multiple times.  Programs with little memory traffic scale
>well, but those that require any reasonable memory access fall flat.  Dual cores
>are not quite that bad but have the same basic problem, two cpus sharing a
>single hypertransport and single memory controller, so each node (AMD
>terminology) has internal contention that the single-core boxes do not.
>
>But the problems are solvable...  except perhaps for the 8-way xeon which is
>just a bad box...  at least the ones I tested on (Dell was one vendor) were...

8 cpu Xeon was great for Diep.

I tested at one of the sheikh's 8 cpu Xeons (no hyperthreading) and
it's very fast.

Latency to memory is around 700ns when all 8 cpu's are busy.

Perhaps not so great for Crafty, but diep can work excellent with it.

>
>>
>>>Thanks again
>>>
>>>Tom



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