Joe Landman wrote: > Contrary to the detractors of the technologies comments, the > TOE/RDMA card *did* provide fairly significant performance delta for > real apps running MPI over gigabit ethernet.
As a detractor of TOEs, I should point out that one data point does not prove that it's common that apps get a benefit. I'd be willing to bet that this app was doing extremely large transfers, and maybe even managed to get more concurrency with the TOE... which could easily be a flaw in the MPI implementation's TCP driver, a pretty common thing to be wrong. For example, LAM was always much better than MPICH over TCP, and I wouldn't be surprised if OpenMPI continues this superiority over MPICH-2. The most interesting thing, to me, is that the various people selling TOEs in the HPC arena publish almost no benchmarks. What's the message rate and N1/2? The only N1/2 I've ever seen published was 100 kbytes. (Obviously I'm not including Myricom in this bucket: they do publish microbenchmarks.) -- greg _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
