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Subject: Re: [OMPI users] Spawn problem
From: Matt Hughes (matt.c.hughes+ompi_at_[hidden])
Date: 2008-03-31 02:03:41


On 30/03/2008, Joao Vicente Lima <joao.lima.mail_at_[hidden]> wrote:
> Hi,
> sorry bring this again ... but i hope use spawn in ompi someday :-D

I believe it's crashing in MPI_Finalize because you have not closed
all communication paths between the parent and the child processes.
For the parent process, try calling MPI_Comm_free or
MPI_Comm_disconnect on each intercomm in your intercomm array before
calling finalize. On the child, call free or disconnect on the parent
intercomm before calling finalize.

Out of curiosity, why a loop of spawns? Why not increase the value of
the maxprocs argument, or if you need to spawn different executables,
or use different arguments for each instance, why not
MPI_Comm_spawn_multiple?

mch

>
> The execution of spawn in this way works fine:
> MPI_Comm_spawn ("./spawn1", MPI_ARGV_NULL, 2, MPI_INFO_NULL, 0,
> MPI_COMM_SELF, &intercomm, MPI_ERRCODES_IGNORE);
>
> but if this code go to a for I get a problem :
> for (i= 0; i < 2; i++)
> {
> MPI_Comm_spawn ("./spawn1", MPI_ARGV_NULL, 1,
> MPI_INFO_NULL, 0, MPI_COMM_SELF, &intercomm[i], MPI_ERRCODES_IGNORE);
> }
>
> and the error is:
> spawning ...
> child!
> child!
> [localhost:03892] *** Process received signal ***
> [localhost:03892] Signal: Segmentation fault (11)
> [localhost:03892] Signal code: Address not mapped (1)
> [localhost:03892] Failing at address: 0xc8
> [localhost:03892] [ 0] /lib/libpthread.so.0 [0x2ac71ca8bed0]
> [localhost:03892] [ 1]
> /usr/local/mpi/ompi-svn/lib/libmpi.so.0(ompi_dpm_base_dyn_finalize+0xa3)
> [0x2ac71ba7448c]
> [localhost:03892] [ 2] /usr/local/mpi/ompi-svn/lib/libmpi.so.0 [0x2ac71b9decdf]
> [localhost:03892] [ 3] /usr/local/mpi/ompi-svn/lib/libmpi.so.0 [0x2ac71ba04765]
> [localhost:03892] [ 4]
> /usr/local/mpi/ompi-svn/lib/libmpi.so.0(PMPI_Finalize+0x71)
> [0x2ac71ba365c9]
> [localhost:03892] [ 5] ./spawn1(main+0xaa) [0x400ac2]
> [localhost:03892] [ 6] /lib/libc.so.6(__libc_start_main+0xf4) [0x2ac71ccb7b74]
> [localhost:03892] [ 7] ./spawn1 [0x400989]
> [localhost:03892] *** End of error message ***
> --------------------------------------------------------------------------
> mpirun noticed that process rank 0 with PID 3892 on node localhost
> exited on signal 11 (Segmentation fault).
> --------------------------------------------------------------------------
>
> the attachments contain the ompi_info, config.log and program.
>
> thanks for some check,
>
> Joao.
>
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