[Beowulf] CCL:Question regarding Mac G5 performance

Konstantin Kudin konstantin_kudin at yahoo.com
Mon May 24 10:45:32 PDT 2004

Joe Landman wrote:

>>  While I can't speak for every code out there, for Gaussian03 I2
>> to work extremely well:
>> http://www.princeton.edu/~kkudin/g03_b5_tests_1.txt

> Looks interesting.  From the text, "All Intel compatible hardware ran
> under RedHat 9.0, in 32 bits."  I presume you ran the I2 as a 64 bit
> using pgf77?  or g77/ifc?  

 I think I2 was using ifc compiler or something like that under a
64-bit OS. It does not seem like PGF or G77 are supported on I2 in
64-bits by Gaussian. 

> Also you used the Atlas libs for p4.  Same
> ones for O16 and O20?

 Yep, it was the same binary version running on all these machines.
After a couple of optimization attempts it appeared that Opteron ran
code optimized for P4 just as quickly as the code that was supposedly
optimized for Opteron, so I simplified the whole thing.

> I would be curious to see the performance with a 64 bit compilation
> running under a 64 bit OS (SuSE 9.x)

 Me too :-) According to this CCL message (and other reliable sources),
the official 64-bit support is just around the corner:

(see reply #2)

 It is unlikely that one can gain much speed from going to 64 bits, but
the support for larger memory and unlimited scratch files is very
worthwhile in itself.


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