[Beowulf] Strange Opteron 2350 performance: Gaussian-03

Mikhail Kuzminsky kus at free.net
Sat Jun 28 13:32:46 EDT 2008

In message from "Li, Bo" <libo at buaa.edu.cn> (Sun, 29 Jun 2008 00:37:12 
The "problem" is present just for Gaussian-03 binary version we have.

If I compile myself Linpack, for example, Opteron 2350 core is faster.
Yes - of course it's Linux x86-64, SuSE 10.3
Powersave daemon is no run.


>Sorry, I don't have the same applications as you.
>Did you compile them with gcc? If gcc, then -o3 can do some 
>-march=k8 is enough I think.
>And you make sure the CPU running at the default frequency. Sometime 
>Powernow is active as default.
>And BTW, what's your platform? Linux? Which release? X86_64?
>Li, Bo
>----- Original Message ----- 
>From: "Mikhail Kuzminsky" <kus at free.net>
>To: "Li, Bo" <libo at buaa.edu.cn>
>Cc: <beowulf at beowulf.org>
>Sent: Sunday, June 29, 2008 12:23 AM
>Subject: Re: [Beowulf] Strange Opteron 2350 performance: Gaussian-03
>> In message from "Li, Bo" <libo at buaa.edu.cn> (Sun, 29 Jun 2008 
>> +0800):
>>>I am afraid there must be something wrong with your experiment.
>>>How did you get the performance? Was your DFT codes running in 
>>>parallel? Any optimization involved?
>> I was afraid the same, but the results are reproduced twice.
>> As I wrote in my message:
>> - there were ONE CORE (one CPU for Opteron 246) runs 
>> - the optimization was performed for OLD Opteron 246 (because 
>> Gaussian, Inc do not propose binaries optimized specially for 
>> Barcelona)
>> DFT test397 (as any other DFT) is parallelized well, and on Opteron 
>> 246 it gives 1.9 times speedup on 2 CPUs. But I didn't run 2-cores 
>> parallelized job for Opteron 2350: I was stressed by results 
>> for 1 core. 
>>>In most of my test, K8L or K10 can beat old opteron at the same 
>>>frequency with about 20% improvement.
>> Sorry, do you have this on Gaussian-03 and for DFT in particular ? 
>> you compile it on K10 using target=barcelona (i.e. optimized for 
>> barcelona) ?  
>> Yours
>> Mikhail
>>>Li, Bo
>>>----- Original Message ----- 
>>>From: "Mikhail Kuzminsky" <kus at free.net>
>>>To: <beowulf at beowulf.org>
>>>Sent: Saturday, June 28, 2008 11:48 PM
>>>Subject: [Beowulf] Strange Opteron 2350 performance: Gaussian-03
>>>> I'm runnung a set of quad-core Opteron 2350 benchmarks, in 
>>>> using Gaussian-03 (binary version from Gaussian, Inc, i.e. 
>>>> by more old - than current - pgf77 version, for Opteron target).
>>>> I compare in particular *one core* of Opteron 2350 w/Opteron 246 
>>>> having the same 2 Ghz frequency and the same amount of cache per 
>>>> (512K L2 + 0.25*2 MB L3 for Opteron 2350 is just 1 MB L2 for Opteron 
>>>> 246). Opteron 246 has even more fast DDR2-667 RAM.
>>>> The Gaussian-03 performance in some cases is close for both 
>>>> (I remember that compilation didn't know about Barcelona !), but for 
>>>> very popular DFT method Opteron 2350 cores looks as slow: one job 
>>>> gives 33% more bad (than Opteron 246) performance. 
>>>> But on standard Gaussian-03 test397.com DFT/B3LYP test: *one* (1) 
>>>> Opteron 2350 core run 15667 sec. (both startstop and cpu) vs 8709 
>>>> on (one) Opteron 246 !! 
>>>> There is no powersaved daemon, so the frequnecy of Opteron 2350 is 
>>>> fixed to 2 Ghz. I reproduced this result twice on Opteron 2350, in 
>>>> particular one time using forced good numactl behaviour. I'm 
>>>> reproducing it on Opteron 246 again :-) but I have indirect 
>>>> confirmation of this timings (based on 2-cpus Opteron 246 parallel 
>>>> test).
>>>> Yes, AFAIK DFT method is cache-friendly, and more slow L3 cache in 
>>>> Opteron 2350 may give more bad performance. But in 1.8 times ??
>>>> Any your comments are welcome.
>>>> Mikhail Kuzminsky
>>>> Computer Assistance to Chemical Research Center
>>>> Zelinsky Institute of Organic Chemistry
>>>> Moscow
>>>> _______________________________________________
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