Re: mpi + shmem issues

From: Anthony Schneider <anthony_at_x-anthony.com>
Date: Mon, 26 May 2003 22:43:24 -0400
i see.  thanks!

-Anthony.

On Mon, May 26, 2003 at 12:39:53PM +1000, Tim Robbins wrote:
> On Sun, May 25, 2003 at 05:17:30PM -0400, Anthony Schneider wrote:
> 
> > 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?
> 
> No, semaphores stay around until they are removed. Perhaps there's an MPI_Xyz
> function you should be calling before your program exits. In any case, you can
> use "ipcs -s" to list semaphores, and "ipcrm -s semid" to remove semaphores.
> 
> It looks like the program is leaking semaphores -- notice how your program
> fails when you run it for the 11th time, and the default maximum number of
> semaphores in the GENERIC kernel is 10 (sysctl kern.ipc.semmni).
> 
> 
> Tim

Received on Mon May 26 2003 - 17:38:41 UTC

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