[Mpi3-rma] MPI-3 UNIFIED model clarification

Sur, Sayantan sayantan.sur at intel.com
Wed Jul 31 12:58:22 CDT 2013

> On 07/31/2013 12:00 PM, Jim Dinan wrote:
> > I would bet that past Jim suggested striking the polling/eventually
> > visibile clause and relying on window synchronization to see updates.
> >   :)
> Yup, so did past, present, and future Pavan.  IMO, that's a useless guarantee.
> > The downside to this is that libraries like SHMEM that rely on passive
> > progress and polling, would not be implementable on top of Unified.
> It's pretty useless even for SHMEM, since the user doesn't know when the
> data is valid.  You could poll on a byte for it to turn to one, but at that point
> you only know about that one byte and nothing else.

Past Sayantan had missed this discussion, but present Sayantan does agree that "eventually" as defined is useless. But he is also confused by the guarantee given by MPI_Win_flush, that when the call returns, all previously issued RMA ops are complete locally and remotely + UNIFIED (public win == private win).

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