<div class="gmail_quote">On Wed, Aug 31, 2011 at 00:29, David Fuentes <span dir="ltr"><<a href="mailto:fuentesdt@gmail.com" target="_blank">fuentesdt@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>when using the "--download-mpi=yes" option on a small cluster,<br>
are the configure scripts able to detect an infiniband switch and<br>
configure/install mpich to communicate over it accordingly ?<br></div></blockquote></div><br><div>MPICH2 does not use InfiniBand, you would use MVAPICH for that. Open MPI should use IB if it is available, but it may not be tuned by default (the system install might not have special tuning either).</div>
<div><br></div><div>Run the programs you care about with -log_summary. If a lot of time is spent in communication, it indicates that the computation you are doing is network-limited and it would likely be worth your time to make the system MPI work for you, otherwise the generic one may be fine.</div>