At 23:37 19.04.2007, [EMAIL PROTECTED] wrote:
I'm not sure exactly which results you are referring to, but keep in mind that you need to divide the overhead by the number of bytes sent. GigE usually sends a lot fewer bytes than InfiniBand.
I ran the benchmark using both IB and Gbe and compared... (and I did the division you refer to above)
The reason for the benchmark showing Gbe to have less overhead than IB is that the overhead associated with Gbe NIC interrupt processing, TCP/IP protocol processing, and socket overhead is mainly handled by kernel threads running on a different core than the MPI process - fooling the benchmark to believe Gbe is more efficient than IB :-) Lessons learned are to be skeptical to benchmarks showing superb result using a single core on a multicore machine ;-)
Håkon _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
