[Beowulf] Re: Beowulf Digest, Vol 45, Issue 28
Hakon.Bugge at scali.com
Thu Nov 22 01:29:46 PST 2007
At 21:00 17.11.2007, Chris Samuel <csamuel at vpac.org> wrote:
>I should also point out that we're using the PGI 7.x series of
>compilers and tell our users to build with:
>so that they get the optimisations for both dual and quad core chips
>(with the appropriate path selected at run time).
While I did the SPEC MPI 2007 for the Barcelona, I got the following
projections (8 nodes, 8 cores per node) for SPECmpiM_base2007:
* PathScale 3.0, -march=core: 5.53
* PathScale 3.0, -march=opteron -msse3: 5.32
* PGI 7.0-7, -tp barcelona-64 + lots of fancy switches: 4.71
* PGI 7.0-7, -tp barcelona-64 -nomovnt -fast: 4.75
I didn't have much time to play with compiler options. It was
interesting to see that the "wrong" architecture was better using the
PathScale compiler. Further, PathScale was significant better than
PGI 7.0-7, even though PGI had support for the "right" architecture.
The switches used for the PathScale compiler can be found at the SPEC
The final rate (5.61) was better, due improved memory bandwidth (due
to a better BIOS).
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