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Subject: Re: [OMPI users] Problem with repeatedly spawning a few processes
From: Ralph Castain (rhc_at_[hidden])
Date: 2009-08-31 21:53:16


Download the nightly 1.3 release branch snapshot - not the actual
release, but the nightly tarball:

http://www.open-mpi.org/nightly/v1.3/

It is very close to release quality - only waiting for a couple of
things, none of which would impact this issue.

Let me know how this works for you.
Ralph

On Aug 31, 2009, at 7:25 PM, Tim Miller wrote:

> Hi,
>
> Thanks -- I downloaded the latest 1.4 snapshot after I saw your
> message and verified that this issue does not seem to occur in it.
> However, I ran into other stability issues (not necessarily
> surprising for a development snapshot). Is there any idea on when
> 1.3.4 will be out and if this fix will be migrated in?
>
> Thanks again very much for your help.
>
> Regards,
> Tim
>
>
> On Wed, Aug 26, 2009 at 6:07 PM, Ralph Castain <rhc_at_[hidden]>
> wrote:
> This is a known issue - I'll test to see if it has been fixed for
> the upcoming 1.3.4. We know the problem does not exist in our devel
> trunk, but I don't know if the fix propagated to the 1.3 branch.
>
>
>
> On Aug 26, 2009, at 3:40 PM, Tim Miller wrote:
>
> Hello Everyone,
>
> I have a problem that I can't seem to figure out from searching the
> mailing list archive. I have a code that repeatedly spawns (via
> MPI_COMM_SPAWN) a group of 8 processes and then waits for them to
> finish. The problem is that OpenMPI (I've tried 1.3.1 and 1.3.3)
> opens a pipe each time MPI_COMM_SPAWN is called, but this pipe never
> gets closed (even if I call MPI_COMM_FREE on both the parent and
> child). Therefore, eventually my master process hits the limit of
> open file descriptors and cannot spawn any more. I cannot figure out
> why this is happening since I am only spawning 8 jobs at a time.
>
> I should note that I don't exchange any data over the child
> intercommunicators -- they exist solely so I can call MPI_BARRIER on
> them (the spawned processes are programed to call MPI_BARRIER
> directly before they call MPI_FINALIZE, thus indicating that they
> are done doing their work).
>
> I'd appreciate any suggestions as to what I might be doing wrong
> with this that is causing OpenMPI to hold the pipes open.
>
> Thanks,
> Tim M.
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