[mpiwg-sessions] Fwd: WPM Session Handle
schuchart at icl.utk.edu
Wed Dec 1 09:26:23 CST 2021
Ping. Any opinions/inputs on this?
-------- Forwarded Message --------
Subject: WPM Session Handle
Date: Sun, 31 Oct 2021 11:08:06 -0400
From: Joseph Schuchart <schuchart at icl.utk.edu>
To: mpiwg-sessions <mpiwg-sessions at lists.mpi-forum.org>
The Hybrid-WG is currently discussing the Continuations proposal. Part
of that proposal is a new continuation request type that is not bound to
any communication operation, and thus not connected to any communicator,
window, or file. That floating state is somewhat disatisfying. We are
thus considering connecting it to a session, i.e., provide a session
handle at creation. This would potentially allow us to isolate the
execution of continuations from different sessions. Unfortunately, this
is not possible at the moment because there is no default session handle
for the WPM model.
From my (arguably uninformed outside) point of view, the WPM is a
special type of session worthy of its own handle (MPI_SESSION_WPM, for
example), which can be used with all functions expecting session handles
as input. As an example, `MPI_Session_get_info(MPI_SESSION_WPM)` would
return an info object containing the "thread_level" info key and the
value passed to MPI_Init_thread (or "single" for MPI_Init). I'm sure
there are other more hairy procedures, but you get the point.
Has this been discussed before? Was there a good reason not to have a
WPM session handle? If not, can we add something like MPI_SESSION_WPM to
allow future API extensions to use session handles?
More information about the mpiwg-sessions