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Subject: Re: [OMPI users] Using MPI_Put/Get correctly?
From: James Dinan (dinan_at_[hidden])
Date: 2010-12-16 10:09:12

On 12/16/2010 08:34 AM, Jeff Squyres wrote:
> Additionally, since MPI-3 is updating the semantics of the one-sided
> stuff, it might be worth waiting for all those clarifications before
> venturing into the MPI one-sided realm. One-sided semantics are much
> more subtle and complex than two-sided semantics.

Hi Jeff,

I don't think we should give users the hope that MPI-3 RMA will be out
tomorrow. The RMA revisions are still in proposal form and need work.
Realistically speaking, we might be able to get this accepted into the
standard within a year and it will be another year before
implementations catch up. If users need one-sided now, they should use
the MPI-2 one-sided API.

MPI-3 RMA extends MPI-2 RMA and will be backward compatible, so anything
you write now will still work. It's still unclear to me whether MPI-3's
RMA semantics will be the leap forward in usability we have hoped for.
We are trying to make it more flexible, but there will likely still be
tricky parts due to portability and performance concerns.

So, my advice: don't be scared of MPI-2. I agree, it's complicated, but
once you get acclimated it's not that bad. Really. :)