[Mpi3-rma] RMA proposal 1 update

[Torsten Hoefler]

On Tue, May 25, 2010 at 09:38:04PM -0500, Rajeev Thakur wrote:
> > > 5:12-14 - Update: "If the window was created with MPI_Win_create,
> the
> > > user is responsible for freeing the window memory after MPI_Win_free
> > > returns. If the window was created with MPI_Win_allocate,
> MPI_Win_free
> > > will free the window memory that was allocated in MPI_Win_allocate."
> > I think we should not prescribe what the user has to do. He might as
> > well choose to never free the memory and this is outside the scope of
> > the MPI standard. I don't see a problem with the current phrasing.
> 
> I wanted to make it clear who is freer rather than saying "can be
> freed", "will be freed" (by whom?). How about this:
> 
> "If the window was created with MPI_Win_create, the user may free the
> window memory after MPI_Win_free returns. If the window was created with
> MPI_Win_allocate, MPI_Win_free will free the window memory that was
> allocated in MPI_Win_allocate."
I don't like the term "user" but I took the second part (which doesn't
sound great but it's clear).

> Or you can say the user may choose to, if he so wishes, free the window
> memory... :-)
Sure. MPI seems to use passive voice more often than active. Check now
:).

> > > 27:38 - Flushall is not useful unless there is a corresponding
> > > lockall/unlockall.
> > I believe this needs to be discussed (I don't think this statement is
> > true).
> 
> MPI_Win_lock allows RMA to a single target rank. How can you do a
> flushall to multiple ranks? Nesting of multiple MPI_Win_lock calls is
> not allowed in the current version of your proposal, is it?
> 
> I thought you were going to add Lockall/Unlockall, but just forgot to
> :-).
That would be easy, however, I didn't have it on my list of things to
add. You're right that it's currently not allowed, however, I meant that
there is more than one way to make use of it (without (un)lockall :).

We shall discuss at the next telecon. I have no objections to adding it.

All the Best,
  Torsten

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Torsten Hoefler         | Research Associate
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