[Mpi3-hybridpm] Meeting agenda for 08/04

[Pavan Balaji]

Hi all,

Sorry, I forgot to send out a reminder earlier about the meeting later 
this morning. But better late than never -- the telecon is at 11am 
central time on 08/04 (today).

Passcode: 85444
Domestic dial number: 888-566-1533
International dial number: 212-547-0383

We got a lot of feedback from the forum, so we have a bunch of things to 
discuss. I've listed this feedback below as agenda items for the 
telecon. Please feel free to add others as needed.

1. Based on discussion at the Forum, we need to formalize high-level
goals of the working group. Specifically, we know that this deals with
interactions with other standards, but we need to narrow down what all
we are considering -- threads, PGAS, ...

2. Define what model we are assuming for threads. As we discussed
earlier, we need to specify what properties we expect in the threads
packages. E.g., we need threads to make asynchronous progress.

3. A bunch of proposals assume that the MPI implementation knows what
the thread local storage is. This might not be true. For MPICH2, it
can be configured with different thread implementations, but there's
no way it can check if the user is using the same thread
package. Maybe we need to add a call that allows the MPI stack get
access to the thread ID (or maybe we can specify some other means to
do this).

4. Discuss Alexander's proposal on thread
registration/deregistration. One of the major comments was that
creating thread-specific communicators for every OpenMP loop is not
realistic. OpenMP does not maintain thread IDs persistently. We'll
probably need more API that allows a communicator to be created once
and each thread to query its rank from the MPI implementation within
each OpenMP loop instead of creating/destroying communicators each
time.

5. Another point that came up is if resource interactions between
different models is being considered, i.e., what resources MPI gets
vs. what resources OpenMP gets.

6. Multi-level hybridness: We are taking a piece-wise approach to
hybridness. We need to allow for multiple stacks to be mixed together,
i.e., MPI+PGAS+threads.

  -- Pavan

-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji