Hi Bogdan,<div><br></div><div>this is exactly the OpenMPI problem I meant (<a href="https://svn.open-mpi.org/trac/ompi/ticket/2043">https://svn.open-mpi.org/trac/ompi/ticket/2043</a>). I only suggested a warning for GCC 4.4.x on x86/x64 because only this is affected. According to the bug descriptions also older Intel CPUs are affected (and not only Nehalem).</div>
<div><br></div><div>Roland</div><div><br><div class="gmail_quote">On Thu, Aug 12, 2010 at 9:55 AM, Bogdan Costescu <span dir="ltr"><<a href="mailto:bcostescu@gmail.com">bcostescu@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 class="im">On Wed, Aug 11, 2010 at 11:58 PM, Roland Schulz <<a href="mailto:roland@utk.edu">roland@utk.edu</a>> wrote:<br>
> OpenMPI 1.4.0 hangs on GCC 4.4.x on x86/x64<br>
<br>
</div>Was this by any chance run on a Nehalem CPU using shared memory ? (not<br>
necessarily sm alone). This particular combination (gcc >= 4.4,<br>
Nehalem, sm) has been known to cause problems which are supposed to be<br>
fixed in OpenMPI 1.4.2. However this problem doesn't manifest itself<br>
on the same computers with older gcc, when not using sm or on<br>
computers with other CPUs. So I think that banning OpenMPI 1.4.0<br>
outright is a too tough measure.<br>
<br>
If you still have access to this combination, could you try running<br>
with 'mpirun -mca btl ^sm ...' ? This should disable sm and allow<br>
other mechanisms to be used for on-node communication (openib or tcp<br>
most likely).<br>
<br>
Cheers,<br>
Bogdan<br>
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