Doug and Jeff have good points (and some good links). On thing to
also pay attention to is the CPU utilization during the bandwidth and
application testing. We found that on our cluster (various Dells
with built in GigE NICs) while we did not see huge differences in
effective bandwidth, the CPU overhead was notably less when using
Jumbo Frames.
Again, YMMV.
Good luck,
-bill
On Jun 11, 2007, at 11:57 AM, Jeffrey B. Layton wrote:
Doug brings up some good points. If you want to try Jumbo
Frames to improve MPI performance you might have to
tweak the TCP buffers as well. There are some links around
the web on this. Sometimes it helps performance, sometimes
it doesn't. Your mileage may vary.
Jeff
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