Re: [OMPI users] 1.7.1 Hang with MPI_THREAD_MULTIPLE set

[Paul Kapinos]

Hello,




http://www.open-mpi.org/faq/?category=supported-systems#thread-support
http://www.open-mpi.org/community/lists/users/2010/03/12345.php







Best,

Paul Kapinos




  print *, 'hello, world!', MPI_THREAD_MULTIPLE, provided







On 05/31/13 06:12, W Spector wrote:

It is more or less well-known that MPI_THREAD_MULTIPLE disable the OpenFabric / InfiniBand networking in Open MPI: On our system not only the 'openib' BTL is off, but also the IPoIB denies to work, leading to error. But I was able to run your programm error-free when completely disabling using the InfiniBand: either both processes on same node (using shared memory), or use "-mca btl ^openib -mca btl_tcp_if_exclude ib0,lo" parameter to the 'mpiexec' in order to disable InfiniBand and IPoIB. Well; this is disappinting due to some 20x loss of performance using Gigagbit Ethernet, comparing the actual InfiniBand... Note: Intel MPI support MPI_THREAD_MULTIPLE when linked with -mt_mpi (Intel and GCC compilers) or -lmpi_mt instead of -lmpi (other compilers). However, Intel MPI is not free. Also, I recommend to _always_ check what kinda of threading lievel you ordered and what did you get:

Dear OpenMPI group,

The following trivial program hangs on the mpi_barrier call with 1.7.1.  I am
using gfortran/gcc 4.6.3 on Ubuntu linux.  OpenMPI was built with
--enable-mpi-thread-multiple support and no other options (other than --prefix).

Are there additional options we should be telling configure about?  Or have we
done something very silly?  Mpich2 works just fine...

Walter Spector


program hang
   use mpi
   implicit none

   integer :: me, npes
   integer :: mpierr, provided
   logical :: iampe0

   call mpi_init_thread (  &
       MPI_THREAD_MULTIPLE,  &
       provided,  &
       mpierr)
   print *, 'hello, world!'

! Hangs here with MPI_THREAD_MULTIPLE set...
   call mpi_barrier (MPI_COMM_WORLD, mpierr)

   call mpi_comm_rank (MPI_COMM_WORLD, me, mpierr)
   iampe0 = me == 0
   call mpi_comm_size (MPI_COMM_WORLD, npes, mpierr)
   print *, 'pe:', me, ', total comm size:', npes
   print *, 'I am ', trim (merge ('PE 0    ', 'not PE 0', iampe0))

   call mpi_finalize (mpierr)

end program
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--
Dipl.-Inform. Paul Kapinos   -   High Performance Computing,
RWTH Aachen University, Center for Computing and Communication
Seffenter Weg 23,  D 52074  Aachen (Germany)
Tel: +49 241/80-24915

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