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Subject: Re: [OMPI users] mpirun hangs when used on more than 2 CPUs
From: Ralph Castain (rhc.openmpi_at_[hidden])
Date: 2012-01-17 09:08:42


You might first just try running a simple MPI "hello" to verify the installation. I don't know if OF is threaded or not.

Sent from my iPad

On Jan 17, 2012, at 5:22 AM, John Hearns <hearnsj_at_[hidden]> wrote:

> 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%e2%80%9d ).
>> 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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>
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