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From: George Bosilca (bosilca_at_[hidden])
Date: 2005-09-19 04:52:48


MPI_Testsome return MPI_UNDEFINED only when in the set of requests there
are no more active requests. Basically at this point the array of requests
(in your example) should contain only MPI_REQUEST_NULL. I check the
different possibilities inside, and I'm pretty confident that we are
correct from the MPI standard point of view. I run your test example and
the behaviour was correct. Moreover, it never miss one request.

Can you forward me your exact example to see what was wrong inside ?

  Thanks,
    george.

On Mon, 19 Sep 2005, George Bosilca wrote:

> Guys I'll take care of that. When I was working on the examples for the
> tutorial here at Euro PVM I notice a similar problem with MPI_Waitsome.
>
> george.
>
> On Sun, 18 Sep 2005, Jeff Squyres wrote:
>
> > Yes -- Tim, can you check? Sounds like something in the request
> > progress is not occurring correctly.
> >
> > Thanks!
> >
> >
> > On Sep 18, 2005, at 5:59 PM, Greg Watson wrote:
> >
> > > Jeff,
> > >
> > > Yes, count is 2, but completed returns 1 on the first call and -32766
> > > on the second call. Sounds like this may be a bug?
> > >
> > > Greg
> > >
> > > On Sep 17, 2005, at 8:11 AM, Jeff Squyres wrote:
> > >
> > >> (composing this in an airport on Saturday; may not actually be sent
> > >> until Monday or so)
> > >>
> > >> -32766 is Open MPI's value for MPI_UNDEFINED. This is what is
> > >> returned
> > >> when there are no active requests in the array that is passed to
> > >> MPI_TESTSOME (see MPI-1.1:.
> > >>
> > >> Just to verify that this behavior isn't a bug, can you confirm some
> > >> things:
> > >>
> > >> - is count > 1?
> > >>
> > >> - if more than one request finished in that single call to
> > >> MPI_TESTSOME
> > >> where completed was returned with a value of 1 (e.g., multiple
> > >> requests
> > >> in your array turned into MPI_REQUEST_NULL), then this is a bug --
> > >> i.e., completed should return an accurate value.
> > >>
> > >>
> > >>
> > >> On Sep 16, 2005, at 8:45 PM, Greg Watson wrote:
> > >>
> > >>
> > >>> Just for a change, I don't have a build problem!
> > >>>
> > >>> However, I have a question about the MPI_Testsome() call. I'm using
> > >>> MPI_Testsome() to check the completion status of a number of
> > >>> outstanding ISend() requests. I'm doing something like this:
> > >>>
> > >>> int outstanding;
> > >>>
> > >>> main()
> > >>> {
> > >>> tids = (int *)malloc(sizeof(int) * count);
> > >>> stats = (MPI_Status *)malloc(sizeof(MPI_Status) * count);
> > >>> reqs = (MPI_Request *) malloc(sizeof(MPI_Request) * count)
> > >>>
> > >>> do_sends();
> > >>>
> > >>> outstanding = count;
> > >>>
> > >>> while (outstanding > 0)
> > >>> check_completed();
> > >>> }
> > >>>
> > >>> do_sends()
> > >>> {
> > >>> for (i = 0; i < count; i++)
> > >>> MPI_ISend(buf, len, MPI_CHAR, i, 0, MPI_COMM_WORLD, &reqs
> > >>> [i]);
> > >>> }
> > >>>
> > >>> check_completed()
> > >>> {
> > >>> int completed;
> > >>>
> > >>> if (MPI_Testsome(count, reqs, &completed, tids, stats) !=
> > >>> MPI_SUCCESS) {
> > >>> printf("error in testsome\n");
> > >>> exit(1);
> > >>> }
> > >>> outstanding -= completed;
> > >>> }
> > >>>
> > >>> The thing is, MPI_Testsome() returns with completed = 1 the first
> > >>> time I call it, then completed = -32766 the second time I call it. It
> > >>> always returns MPI_SUCCESS though.
> > >>>
> > >>> Does anyone know what's going on? Am I doing something dumb?
> > >>>
> > >>> Thanks,
> > >>>
> > >>> Greg
> > >>> _______________________________________________
> > >>> devel mailing list
> > >>> devel_at_[hidden]
> > >>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
> > >>>
> > >>>
> > >>
> > >> --
> > >> {+} Jeff Squyres
> > >> {+} The Open MPI Project
> > >> {+} http://www.open-mpi.org/
> > >>
> > >> _______________________________________________
> > >> devel mailing list
> > >> devel_at_[hidden]
> > >> http://www.open-mpi.org/mailman/listinfo.cgi/devel
> > >>
> > >
> > > _______________________________________________
> > > devel mailing list
> > > devel_at_[hidden]
> > > http://www.open-mpi.org/mailman/listinfo.cgi/devel
> > >
> >
> >
>
> "We must accept finite disappointment, but we must never lose infinite
> hope."
> Martin Luther King
>
> _______________________________________________
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>

"We must accept finite disappointment, but we must never lose infinite
hope."
                                  Martin Luther King