This should not happen. Typically, Intra node communication latency are way way cheaper than inter node.
Can you please tell us how u ran your application ?
Sent from my iPhone
On Jun 1, 2012, at 7:34 AM, Mudassar Majeed <mudassarm30_at_[hidden]> wrote:
> Dear MPI people,
> Can someone tell me why MPI_Ssend takes more time when two MPI processes are on same node ...... ?? the same two processes on different nodes take much less time for the same message exchange. I am using a supercomputing center and this happens. I was writing an algorithm to reduce the across node communication. But now I found that across node communication is cheaper than communication within a node (with 8 cores on each node).
> best regards,
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