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Subject: [OMPI users] Can NWChem be run with OpenMPI over an InfiniBand interconnect ... ??
From: Richard Walsh (Richard.Walsh_at_[hidden])
Date: 2010-05-06 14:06:13


All,

I have built NWChem successfully, and trying to run it with an
Intel built version of OpenMPI 1.4.1. If I force to run over over
1 GigE maintenance interconnect it works, but when I try it over
the default InfiniBand communications network it fails with:

--------------------------------------------------------------------------
An MPI process has executed an operation involving a call to the
"fork()" system call to create a child process. Open MPI is currently
operating in a condition that could result in memory corruption or
other system errors; your MPI job may hang, crash, or produce silent
data corruption. The use of fork() (or system() or other calls that
create child processes) is strongly discouraged.

The process that invoked fork was:

  Local host: gpute-2 (PID 15996)
  MPI_COMM_WORLD rank: 0

If you are *absolutely sure* that your application will successfully
and correctly survive a call to fork(), you may disable this warning
by setting the mpi_warn_on_fork MCA parameter to 0.
--------------------------------------------------------------------------

This looks to be a known problem. Is there I go around? I have seen
it suggested in some places that I need to use Mellanox's version of MPI,
which is not an option and surprises me as they are a big OFED contributor.

What are my options ... other than using GigE ... ??

Thanks,

rbw

   Richard Walsh
   Parallel Applications and Systems Manager
   CUNY HPC Center, Staten Island, NY
   718-982-3319
   612-382-4620

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