A colleague of mine ran some microkernels on an 8-way Barcelona box (Sun x2200M2 at 2.3 GHz). Here are some performance comparisons with Scali. The performance tests are modified versions of the HPCC pingpong tests. The OMPI version is the trunk with my "single-queue" fixes... otherwise, OMPI latency at higher np would be noticeably worse.

             latency(ns)   bandwidth(MB/s)
           (8-byte msgs)   (2M-byte msgs)
           =============    =============
     np    Scali    OMPI    Scali    OMPI

      2      327     661     1458    1295
      4      369     670     1517    1287
      8      414     758     1535    1294

OMPI latency is nearly 2x slower than Scali's. Presumably, "fastpath" PML latency optimizations would help us a lot here. Thankfully, our latency is flat with np with the recent "single-queue" fixes... otherwise our high-np latency story would be so much worse. We're behind on bandwidth as well, though not as pitifully so.

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