Date: Sun, 25 May 2003 17:17:30 -0400 From: Anthony Schneider <anthony@x-anthony.com> To: freebsd-current@freebsd.org Subject: Re: mpi + shmem issues Message-ID: <20030525211730.GA5226@x-anthony.com> In-Reply-To: <20030525064929.GA96588@x-anthony.com> References: <20030525064929.GA96588@x-anthony.com>
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additional information:
when recompiling mpich for debugging symbols, configure fails on:
checking that usable shared memory locks were found... no
so, does this mean that mpich somehow exhausted all shmem locks?
after running the program only 10 times, i see this as infeasible,
considering
a) mpich (presumably in MPI_Init()) would only want 1 or
2 locks on init
and
b) any shared memory locks mpich grabs should be freed
upon process completion (whether clean or not) by the
operating system, no?
well, configure with --with-device=ch_shmem:-usesysv succeeds
(checking that usable shared memory locks were found... yes), so
I will try this out.
But for reference, can anyone make a guess as to why/how a shared
memory application can exhaust locks like this?
thank you.
-Anthony.
On Sun, May 25, 2003 at 02:49:30AM -0400, Anthony Schneider wrote:
> Hello,
> My machine is a dual athlon:
> FreeBSD pickle. 5.1-BETA FreeBSD 5.1-BETA #6: Sun May 25 02:16:15 EDT 2003
> anthony@pickle.:/usr/src/sys/i386/compile/PICKLE i386
>
> I started having this issue, which may or may not exist on uniprocessor
> systems or 4.x systems. I built mpi with ch_shmem device for shared memory
> programs (instead of the more common rsh/ssh), and something strange
> happens. For even the most basic little program, the program will launch
> fine (usually) the first time i run it after the system boots, but after a
> few executions, execution starts failing consistently until after i reboot.
>
> as an example, here is a small acknowledgment program:
>
> #include <mpi.h>
> #include <stdio.h>
>
> int main (int argc, char *argv[]) {
> int mpiRank, mpiSize;
>
> MPI_Init (&argc, &argv);
> MPI_Comm_rank (MPI_COMM_WORLD, &mpiRank);
>
> printf ("#%d here\n", mpiRank);
>
> return 0;
>
> }
>
> and here is the history of executing it:
>
> pickle:anthony:/home/anthony/src/mpi:6% mpirun -np 2 ./foo
> #0 here
> #1 here
> Child process exited unexpectedly 0
> Abort trap (core dumped)
> pickle:anthony:/home/anthony/src/mpi:7% mpirun -np 2 ./foo
> #0 here
> pickle:anthony:/home/anthony/src/mpi:8% #1 here
>
> pickle:anthony:/home/anthony/src/mpi:8% mpirun -np 2 ./foo
> #0 here
> #1 here
> pickle:anthony:/home/anthony/src/mpi:9% mpirun -np 2 ./foo
> #0 here
> #1 here
> pickle:anthony:/home/anthony/src/mpi:10% mpirun -np 2 ./foo
> #1 here
> #0 here
> Child process exited unexpectedly 0
> Abort trap (core dumped)
> pickle:anthony:/home/anthony/src/mpi:11% mpirun -np 2 ./foo
> #0 here
> #1 here
> Child process exited unexpectedly 0
> Abort trap (core dumped)
> pickle:anthony:/home/anthony/src/mpi:12% mpirun -np 2 ./foo
> #0 here
> #1 here
> pickle:anthony:/home/anthony/src/mpi:13% mpirun -np 2 ./foo
> #1 here
> #0 here
> Child process exited unexpectedly 0
> Abort trap (core dumped)
> pickle:anthony:/home/anthony/src/mpi:14% mpirun -np 2 ./foo
> #0 here
> #1 here
> pickle:anthony:/home/anthony/src/mpi:15% mpirun -np 2 ./foo
> #0 here
> #1 here
> pickle:anthony:/home/anthony/src/mpi:16% mpirun -np 2 ./foo
> semget failed for setnum = 0
> Abort trap (core dumped)
> pickle:anthony:/home/anthony/src/mpi:17% mpirun -np 2 ./foo
> semget failed for setnum = 0
> Abort trap (core dumped)
> pickle:anthony:/home/anthony/src/mpi:18% mpirun -np 2 ./foo
> semget failed for setnum = 0
> Abort trap (core dumped)
>
> ... (continues until i reboot)
>
> the first run that aborts is strange, but since it is not something
> i've witnessed previously, i'd like to forget that and focus on
> the repeated semget failures. i would normally be looking into
> the mpi implementation (mpich 1.2.5), but since after semget fails
> once it never seems to succeed again with other mpi programs, i
> think this to be a freebsd problem.
>
> i'm runing a (barely) custom kernel, with nothing added to it.
> i just cvsup'd and rebuilt less than an hour ago, and the problem
> has persisted from beta #5 through beta #6.
>
> any suggestions?
>
> thank you for your help.
>
> -Anthony.
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