Tom Crockett wrote:
> We have an application that is exhibiting very poor performance in a
> section of code dominated by calls to various MPI collectives.
After a few weeks of experimentation, we are now convinced this is not a
LAM issue, but rather a problem with the bge Gigabit Ethernet driver in
Solaris 10 x86. If we run the same executable on the same nodes using
IP over InfiniBand instead of IP over Gigabit Ethernet, the performance
discrepancy disappears. So LAM 7's collectives perform just fine :-)
-Tom
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Tom Crockett
College of William and Mary email: tom_at_[hidden]
Computational Science Cluster phone: (757) 221-2762
Savage House fax: (757) 221-2023
P.O. Box 8795
Williamsburg, VA 23187-8795
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