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Subject: Re: AMD Opteron 2 x 248

Author: Anthony Cozzie

Date: 10:14:56 05/17/04

Go up one level in this thread


On May 17, 2004 at 00:40:24, Robert Hyatt wrote:

>On May 17, 2004 at 00:19:00, Tom Likens wrote:
>
>>On May 16, 2004 at 20:57:34, Robert Hyatt wrote:
>>
>>>On May 16, 2004 at 19:10:30, Tom Likens wrote:
>>>
>>>>On May 16, 2004 at 16:54:10, Robert Hyatt wrote:
>>>>
>>>>>On May 16, 2004 at 15:39:18, Anthony Cozzie wrote:
>>>>>
>>>>>>On May 16, 2004 at 13:56:23, Tom Likens wrote:
>>>>>>
>>>>>>>On May 16, 2004 at 13:17:17, Anthony Cozzie wrote:
>>>>>>>
>>>>>>>>On May 16, 2004 at 11:10:01, Omid David Tabibi wrote:
>>>>>>>>
>>>>>>>>>On May 16, 2004 at 11:05:36, Anthony Cozzie wrote:
>>>>>>>>>
>>>>>>>>>>On May 16, 2004 at 10:14:07, K. Burcham wrote:
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>Has anyone here posted using dual 248s?
>>>>>>>>>>>wonder how 2 x 248 AMD compares to dual Xeon 3.2 with 1 meg cache running a 32
>>>>>>>>>>>bit commercial chess program?
>>>>>>>>>>>
>>>>>>>>>>>http://www.newegg.com/app/viewProductDesc.asp?description=19-103-433&depa=0
>>>>>>>>>>>
>>>>>>>>>>>http://www.monarchcomputer.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=M&Product_Code=120140
>>>>>>>>>>>
>>>>>>>>>>>kburcham
>>>>>>>>>>
>>>>>>>>>>Like Mike, I have dual 246s.  Opteron is a great CPU, but the 64-bit software
>>>>>>>>>>isn't *quite* ready, at least on linux (imo).
>>>>>>>>>
>>>>>>>>>Running 32 bit chess engines on that system, how much speedup do you see in
>>>>>>>>>comparison to the fastest 32 bit dual system?
>>>>>>>>
>>>>>>>>I wouldn't know.  I only run 64 bit linux :)  It works pretty well, but there
>>>>>>>>are definitely a few bugs left.  I'd say in another 3 months my system will be
>>>>>>>>good enough for me (new nvidia drivers, a few more kernel versions).
>>>>>>>>
>>>>>>>>anthony
>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>anthony
>>>>>>>
>>>>>>>Anthony,
>>>>>>>
>>>>>>>Are you running 64-bit SUSE or one of the Red Hat flavors?  I've got an FX-51
>>>>>>>that I initially loaded 32-bit SUSE on (this was before SUSE supported SATA
>>>>>>>drives right out of the box) and was pleasantly surprised at how fast the
>>>>>>>32-bit programs ran (chess engines included).  When I finally installed the
>>>>>>>64-bit version, I was unpleasantly surprised at how *slow* the 32-bit software
>>>>>>>ran (including and especially the various Linux engines I test against).
>>>>>>>
>>>>>>>I got the requiste 64-bit boost when I converted Djinn over to a true 64-bit
>>>>>>>program but was somewhat dismayed with the 32-bit slowdown of its sparring
>>>>>>>partners.  I *could* dual-boot into a 32-bit version of Linux for testing but
>>>>>>>frankly that offends my sensibilities and seems like a bit of a waste.
>>>>>>>
>>>>>>>regards,
>>>>>>>--tom
>>>>>>
>>>>>>Hmm, I haven't tried.  I usually test against crafty, and I compiled a version
>>>>>>in 64-bit mode.  I would have thought that 32 bit apps would run quickly because
>>>>>>this is essentially _hardware_ emulation, but maybe not . . . .
>>>>>>
>>>>>>anthony
>>>>>
>>>>>
>>>>>I don't see his problem.  32 bit code runs the same on a 32 bit or 64 bit
>>>>>operating system.  The opteron just doesn't get to use all its "stuff" in 32 bit
>>>>>mode.  I (and others) have done this several times and didn't see a 32 bit
>>>>>program run slower on a 64 bit O/S...
>>>>>
>>>>>Not sure what is going on there...
>>>>
>>>>Hey Bob,
>>>>
>>>>Unfortunately, I can't recreate the numbers now since I got rid of the
>>>>32-bit version of SUSE on the FX.  From memory what I saw was that if I
>>>>compiled my program under 32-bit SUSE, using the Intel 7.1 compiler and
>>>>profile-guided optimizations, I got about 1.1M nps.  So far, so good, but
>>>>when I switched over to the 64-bit version and compiled the exact same
>>>>program (in the same manner) I could only get a top speed of about 450k nps.
>>>>
>>>>I didn't really worry about it too much since I was converting the program
>>>>over to 64-bits (which gave me all the speed back and a bit more).  My
>>>>assumption was that it was a problem with the 32-bit version of the
>>>>libraries, but now I'm not so sure (especially, if I'm the only one seeing
>>>>the problem).  I may try a couple of experiments tonight to either verify or
>>>>invalidate the old results.
>>>>
>>>>regards,
>>>>--tom
>>>
>>>
>>>
>>>Really makes no sense.  The only thing different is that the O/S has to
>>>save/restore extra stuff when context switching (extra registers, etc).  I have
>>>not tried your experiment however.  I ran Suse-64 on the quad opteron I used,
>>>and I compiled for 32 bit or 64 bit by simply telling gcc which architecture to
>>>produce object code for.  I didn't find any difference on normal 32 bit stuff,
>>>although Crafty ran significantly faster compiled for 64 bit, however.  AMD is
>>>putting together a demo to show the difference as they market the 64 bit
>>>performance...
>>
>>You may well be right.  I ran some simple tests this evening and the 32-bit
>>executable of the program was pretty fast (700K+ nps) which was faster than
>>I remember.  This is especially significant since the changes I've been
>>making lately have slowed the NPS down somewhat, so this number is not that
>>far off the 64-bit version.  It could be (i.e. it's likely) that I had
>>something incorrectly configured initially.  I've also patched the 64-bit
>>version of SUSE (to the tune of about 208MB using the "9.0-PatchCD.iso"
>>image off their website) since installing it to correct for the SATA drives.
>>So unfortunately, at the end of the day it's probably not an apples-to-apples
>>comparision.  Anyway, my moneys on operator error ;)
>>
>>BTW, are you still running 64-bit SUSE or did you switch over to Red Hat?
>>
>>regards,
>>--tom
>
>
>The 4-way box was AMD's.  They were running 64 bit Suse.  They have a
>"relationship" with them but I am not sure how much I can say about it as I
>don't know what is public knowledge...
>
>We will have a bunch of dual opterons soon.  We'll have to make that choice but
>I suspect Suse...

My favorite distro has been Debian for some years, because I like their package
system.  Debian has true dependency support: You can upgrade packages
individually.  With RPMs you technically can, but RedHat/Suse/Mandrake really
prefer if you just upgrade with each version every 6 months.

I ran on Debian at CCT6, but Debian's x86-64 support is quite poor.  Right now
I'm trying Gentoo linux and things have been working pretty well.  Gentoo has
actually impressed me quite a bit.  And compiling is pretty fast when you have a
dual system :)

When is your cluster going to be ready?

anthony



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