Can we discuss this on the WG telecon (which the chair needs to restart)? I'd like to first put together rough thoughts on the semantics in slides before writing up text. Specific issues to clarify: 1. What happens when one thread is waiting on an iflush request while another thread keeps posting more operations. 2. What are the ordering semantics for two consecutive nonblocking iflush operations? Can they finish out of order? If they finish out of order, what are the semantics of accumulate operations with these epochs? Are they ordered? 3. What are the semantics of put operations in two nonblocking epochs? Can they overwrite each other? There might be more issues that need clarification too. I'm happy to make slides discussing a first draft of these (and more perhaps), but I don't want the discussion to be over email. -- Pavan Sent from my iPhone

On Dec 10, 2014, at 2:57 PM, Jeff Hammond <[email protected]> wrote:

We really need a ticket i.e. a substantive written proposal for iflush, etc. in order to make progress on the umbrella topic that includes it and #459.

Pavan: Please let me know when you will have something for this.

Jeff

---------- Forwarded message ---------- From: MPI Forum <[email protected]> Date: Wed, Dec 10, 2014 at 11:11 AM Subject: Re: [MPI Forum] #459: RMA sync ops with vector of windows To:

#459: RMA sync ops with vector of windows -------------------------------------+------------------------------------- Reporter: jhammond | Owner: jhammond Type: New routine(s) | Status: assigned Priority: Not ready / author | Milestone: 2014/12/08 rework | California, USA Version: MPI 4.0 | Resolution: Keywords: RMA | Implementation status: Waiting -------------------------------------+-------------------------------------

Comment (by gropp):

The WG found this interesting, but notes that there are alternatives that may provide the same capability. These include nonblocking flush. In a straw vote, iflush received 11 votes and nflush received 3; in contrast, nsync received 9 and isync received 4.

-- Ticket URL: <https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/459#comment:3> MPI Forum <https://svn.mpi-forum.org/> MPI Forum

-- Jeff Hammond [email protected] http://jeffhammond.github.io/ _______________________________________________ mpiwg-rma mailing list [email protected] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-rma