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Subject: Re: [OMPI users] mpirun hangs when used on more than 2 CPUs ( mpirun compiled without thread support )
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2012-01-19 09:24:53

On Jan 18, 2012, at 4:15 AM, Theiner, Andre wrote:

> I also have requested the user to run the following adaption to his original
> command "mpriun -np 9 interFoam -parallel". I hoped to get a kind of debug output
> which points me into the right way. The new command did not work and I am a bit lost.
> Is the syntax wrong somehow or is there a problem in the user's PATH?
> I do not understand what debugger is wanted. Does mpirun not have an internal debugger?
> testuser_at_caelde04:~/OpenFOAM/testuser-2.0.1/nozzleFlow2D> mpirun -v --debug --debug-daemons -np 9 interfoam -parallel
> --------------------------------------------------------------------------
> A suitable debugger could not be found in your PATH.
> Check the values specified in the orte_base_user_debugger MCA parameter for the list of debuggers that was searched.

The --debug option is probably not doing what you think in this case. Here's what the man page says:

       For debugging:

       -debug, --debug
              Invoke the user-level debugger indicated by the
              orte_base_user_debugger MCA parameter.

       -debugger, --debugger
              Sequence of debuggers to search for when --debug is used (i.e.
              a synonym for orte_base_user_debugger MCA parameter).

       -tv, --tv
              Launch processes under the TotalView debugger. Deprecated back-
              wards compatibility flag. Synonym for --debug.

Hence, the --debug flag is trying to invoke a parallel debugger. It doesn't actually show debug-level information about what is happening in mpirun or the MPI processes.

Jeff Squyres
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