[Beowulf] [gorelsky at stanford.edu: CCL:dual-core Opteron 275performance]

Mikhail Kuzminsky kus at free.net
Tue Jul 5 12:33:56 EDT 2005


In message from Alan Louis Scheinine <scheinin at crs4.it> (Tue, 05 Jul 
2005 14:07:20 +0200):
>With regard to performance of dual-core Opteron, your milage may 
>vary.
>I just finished a benchmark using a program that needs a high
>bandwidth to memory. 
Yes, it's good idea.

> A quad-CPU board with single-core Opteron was
>nearly twice as fast as a dual-CPU board with dual-core Opteron,
But this result means, that 4 cores of Opteron are "equal by 
performance" to 2 "single core" Opterons. If it'll be *exactly*,
your program looks as working "only" w/RAM (I suppose that
memory throughput don't scale from single core Opteron to 2-cores 
chip, what is, generally speaking, incorrect), and there is
practically no "memory-independed" computations !

But I understand that some typical finite elements theory loops  
may contain a lot of memeory references.

I plan to receive Opteron275 dual cpu server in pair of days,
and also to perform a set of tests.

Yours
Mikhail

>in each case four MPI processes; compiled with MPICH with PGI;
>in every case 2.2 GHz CPU frequency.  The program is meteorology,
>short-term weather prediction.
>
>-- Alan
>
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