[Beowulf] Strange Opteron 2350 performance: Gaussian-03

Mikhail Kuzminsky kus at free.net
Mon Jun 30 17:23:19 EDT 2008


In message from Bernd Schubert <bernd-schubert at gmx.de> (Sat, 28 Jun 
2008 19:04:50 +0200):
>On Saturday 28 June 2008, Li, Bo wrote:
>> Hello,
>> Sorry, I don't have the same applications as you.
>> Did you compile them with gcc? If gcc, then -o3 can do some 
>>optimization.
>> -march=k8 is enough I think.
>
>As Mikhail wrote in his first mail, he uses binaries from Gaussian 
>Inc. Can 
>gfortran in the mean time compile gaussian? Even if it can, it might 
>be a 
>problem for publications, since the only officially supported 
>compiler is 
>pgf77.
>Mikhail, do you have the source at all? Due to the different cache 
>model of 
>the barcelona a recompilation might really help.

No, I have no source :-( I absolutely agree w/you - DFT used is 
cache-friendly. Moreover, this big performance gap corresponds to DFT 
w/FMM (Fast Multipole Method). For "usual" DFT, Opteron 2350 cores are 
also more "slow" than Opteron 246, bun "only" on 33%.   

>
>> And you make sure the CPU running at the default frequency. Sometime
>
>Yeah, can you check the scaling governor isn't set to ondemand or 
>conservative?

Yes, I looked to frequency many times (as a crazy :-)). There is no 
powersaved daemon, and I looked only 2 Ghz in /proc/cpuinfo :-) 

Yours
Mikhail

>
>
>Cheers,
>Bernd
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