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Large vs Small computer nodes

    Question

  • When designing a cluster, is there any performance gain for running say 8 compute node at 12 core per node as opposed to 2 compute nodes running 48 core per node, assuming total ram and CPU speed stay consistant. I have been told that core to core communication between compute nodes would be slower on the 2 node cluster since there would be only one (2) infiniband cables routing the traffic as opposed to 8, thus causing a bottleneck. Is this true?
    Tuesday, November 30, 2010 6:33 PM

Answers

  • In general, you should have better performance with fewer nodes that have more cores.  I don't think you can change the fact that internode connectivity will always add latency and bandwidth constraints.

    However, with Infiniband and/or 10GigE solutions that Microsoft tests (i.e. "logo's") to use 'Network Direct' (RDMA) for MPI applications (for example), we're striving to minimize that internode bottleneck.

    --Brian

    Sunday, January 2, 2011 9:49 AM