[mpiwg-rma] [Mpi-forum] 3/14: Formal Readings

[Jim Dinan]

Rolf,

I think this ticket needs to be reviewed by the RMA WG before moving it
forward.  I would suggest updating the text to incorporate the following
changes:

Example 11.13 demonstrates the proper synchronization in the unified memory
model when a data transfer is implemented with load and store (instead of
MPI_PUT or MPI_GET) and the synchronization between processes is performed
using point-to-point communication. The synchronization between processes
must be supplemented with a memory synchronization through calls to
MPI_WIN_SYNC, which act locally as a processor-memory barrier.  In Fortran,
reordering of the MPI_WIN_SYNC calls must be prevented with MPI_F_SYNC_REG
operations.

The variable X is contained within a shared memory window and X corresponds
to the same memory location at both processes. The MPI_WIN_SYNC operation
performed by process A ensures completion of the load/store operations
issued by process A. The MPI_WIN_SYNC operation performed by process B
ensures that process A's updates to X are visible to process B.
In the example, I don't see the reason for the second set of SYNC
operations after B's read of X.  If A updates X and B only reads it, the
second send/recv synchronization should be sufficient.  That is, B has not
made any updates to X that need to be made visible A, and B's read of X
will be ordered because of the send operation.  The F_SYNC could still be
needed to preserve this ordering.

 ~Jim.


On Mon, Feb 17, 2014 at 12:23 PM, Jeff Hammond <jeff.science at gmail.com>wrote:

> Switching to the WG list so that everyone is involved...
>
> I do not see adding an example as so urgent that it needs to be dealt
> with at the next meeting, given how overloaded the relevant people
> are.
>
> Honestly, it is more likely to be read by users if the example and
> commentary on it are the subject of a blog post on Squyres' blog.  At
> the very least, that will ensure Google indexes it and thus curious
> people will find it (as much cannot be said for the MPI standard
> itself).
>
> Jeff
>
> On Mon, Feb 17, 2014 at 10:50 AM, Rolf Rabenseifner
> <rabenseifner at hlrs.de> wrote:
> > Pavan,
> >
> > do you put also #413 on the list.
> > I believe, it's better to have it on the list
> > although it is only an example and therefore the RMA group
> > may put it on the errata without plenary.
> > Please can you do all what is needed
> > that it comes on the MPI-3.0 errata list.
> >
> > Best regards
> > Rolf
> >
> >> Pavan,
> >>    thank you for supporting it in the March meeting (Rajeev will not
> >>    be there).
> >>    Is there a RMA WG Meeting at the March Forum Meeting?
> >>    Will you do an MPI-3.0 errata plenary reading
> >>    or will you put it into the errata by WG dicision,
> >>    because it is only an example?
> >>    In both cases #413 should be latest tomorrow on the agenda.
> >>
> >>    Because it is one block of text at one precise location,
> >>    the ticket format may be enough formalism, i.e., no extra pdf.
> >
> > ----- Original Message -----
> >> From: "Jim Dinan" <james.dinan at gmail.com>
> >> To: "Main MPI Forum mailing list" <mpi-forum at lists.mpi-forum.org>
> >> Sent: Monday, February 17, 2014 4:35:51 PM
> >> Subject: [Mpi-forum] 3/14: Formal Readings
> >>
> >>
> >>
> >> Hi All,
> >>
> >>
> >> The RMA and Hybrid working groups would like to put forward the
> >> following tickets for formal readings at the upcoming meeting:
> >>
> >>
> >> #380 - Endpoints proposal
> >>
> >>
> >>
> https://svn.mpi-forum.org/trac/mpi-forum-web/attachment/ticket/380/mpi-report.pdf
> >>
> >>
> >> Read by: Pavan Balaji
> >>
> >>
> >> #349, #402, #404 - Address arithmetic proposal
> >>
> >>
> >>
> >>
> https://svn.mpi-forum.org/trac/mpi-forum-web/attachment/ticket/349/review-349-402-404.pdf
> >>
> >>
> >>
> >> Read by: David Goodell
> >> #369 - Add same_disp_unit info key for RMA window creation
> >>
> >>
> >>
> >>
> https://svn.mpi-forum.org/trac/mpi-forum-web/attachment/ticket/369/mpi-report.2.pdf
> >>
> >>
> >>
> >> Read by: Pavan Balaji
> >>
> >> Please add these to the agenda.  Unfortunately, I will not be able to
> >> attend this meeting, so I have included a contact person for each
> >> ticket.
> >>
> >>
> >> Thanks!
> >>  ~Jim.
> >> _______________________________________________
> >> mpi-forum mailing list
> >> mpi-forum at lists.mpi-forum.org
> >> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum
> >
> > --
> > Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner at hlrs.de
> > High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530
> > University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832
> > Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner
> > Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307)
>
>
>
> --
> Jeff Hammond
> jeff.science at gmail.com
> _______________________________________________
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> mpiwg-rma at lists.mpi-forum.org
> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-rma
>
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