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Subject: Re: [OMPI users] mpirun hangs when used on more than 2 CPUs
From: John Hearns (hearnsj_at_[hidden])
Date: 2012-01-17 07:22:25


Andre,
you should not need the OpenMPI sources.

Install the openmpi-devel package from the same source
(zypper install openmpi-devel if you have that science repository enabled)
This will give you the mpi.h file and other include files, libraries
and manual pages.

That is a convention in Suse-style distros - the devel package
contains the stuf you need to 'develop'

On 17/01/2012, Theiner, Andre <andre.theiner_at_[hidden]> wrote:
> Hi Devendra,
> thanks for your interesting answer, up to now I expected to get a fully
> operational openmpi installation package
> by installing openmpi from the “science” repository (
> http://download.opensuse.org/repositories/science/openSUSE_11.3%94 ).
> To compile your script I need to have the openmpi sources which I do not
> have at present, I will try to get them.
> How do I compile and build using multiple processors?
> Is there a special flag which tells the compiler to care for multiple CPUs?
>
> Andre
>
>
> From: users-bounces_at_[hidden] [mailto:users-bounces_at_[hidden]] On
> Behalf Of devendra rai
> Sent: Montag, 16. Januar 2012 13:25
> To: Open MPI Users
> Subject: Re: [OMPI users] mpirun hangs when used on more than 2 CPUs
>
> Hello Andre,
>
> It may be possible that your openmpi does not support threaded MPI-calls (if
> these are happening). I had a similar problem, and it was traced to this
> cause. If you installed your openmpi from available repositories, chances
> are that you do not have thread-support.
>
> Here's a small script that you can use to determine whether or not you have
> thread support:
>
> #include <mpi.h>
> #include <iostream>
> int main(int argc, char **argv)
> {
> int myrank;
> int desired_thread_support = MPI_THREAD_MULTIPLE;
> int provided_thread_support;
>
> MPI_Init_thread(&argc, &argv, desired_thread_support,
> &provided_thread_support);
>
> /* check if the thread support has been provided */
> if (provided_thread_support!=desired_thread_support)
> {
> std::cout << "MPI thread support not available! Aborted. " <<
> std::endl;
> exit(-1);
> }
> MPI_Finalize();
> return 0;
> }
>
> Compile and build as usual, using multiple processors.
>
> Maybe this helps. If you do discover that you do not have support available,
> you will need to rebuild MPI with --enable-mpi-threads=yes flag.
>
> HTH.
>
>
> Devendra
>
> ________________________________
> From: "Theiner, Andre" <andre.theiner_at_[hidden]>
> To: "users_at_[hidden]" <users_at_[hidden]>
> Sent: Monday, 16 January 2012, 11:55
> Subject: [OMPI users] mpirun hangs when used on more than 2 CPUs
>
>
> Hi everyone,
> may I have your help on a strange problem?
> High performance computing is new to me and I have not much idea about
> OpenMPI and OpenFoam (OF) which uses the “mpirun” command.
> I have to support the OF application in my company and have been trying to
> find the problem since about 1 week.
> The versions are openmpi-1.3.2 and OF 2.0.1 which are running on openSUSE
> 11.3 x86_64.
> The computer is brand new, has 96 GB RAM, 12 CPUs and was installed with
> Linux some weeks ago.
> I installed OF 2.0.1 according to the vendors instructions at
> http://www.openfoam.org/archive/2.0.1/download/suse.php.
>
> Here the problem:
> The experienced user tested the OF with a test case out of one of the
> vendors tutorials.
> He only used the computing power of his local machine “caelde04” , no other
> computers were accessed by mpirun.
>
> He found no problem when testing in single “processor mode” but in
> “multiprocessor mode” his calculations hangs when he distributes
> the calculations to more than 2 CPUs. The OF vendor thinks this is an
> OpenMPI problem somehow and that is why I am trying to get
> help from this forum here.
> I attached 2 files, one is the “decomposeParDict” which resides in the
> “system” subdirectory of his test case and the other is the log file
> from the “decomposePar” command and the mpirun command “mpirun -np 9
> interFoam –parallel”.
> Do you have an idea where the problem is or how I can narrow it down?
> Thanks much for any help.
>
> Andre
>
>
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