[Mpi3-hybridpm] MPI-3 Hybrid Telecon Minutes

[Pavan Balaji]

All,

Here are the meeting minutes for today's call. I'll be putting this up 
on the wiki and sending out the slides and ticket pointers as promised soon.

Attendees: Pavan Balaji, Weikuan Yu, Edgar Gabriel, Brian Smith, Jeff 
Squyres, Rajeev Thakur, Steve Oyanagi, Jim Dinan, Marc-Andre Hermanns, 
Torsten Hoefler, Sameer Kumar, Jeremiah.

Minutes:

  * Discussed some of the proposals that have been submitted for the 
Hybrid working group. Currently we have four (treating threads as 
processes, dynamic thread levels, thread init/finalize routines for 
thread-core mapping, MPI progress query semantics).

  * The first proposal was not discussed; we will wait for Alexander to 
join to describe it.

  * We discussed the dynamic thread levels proposal where an application 
can give a hint to the MPI library about the thread-level it needs. For 
this, we discussed some of the problems implementations might have 
including (i) collective operations that behave in one way when in 
THREAD_MULTIPLE mode and in another way in other modes and (ii) dealing 
with asynchronous progress threads.

  * We discussed the thread init/finalize proposal, where a thread can 
optionally explicitly tell the MPI implementation that it exists, so the 
MPI library can, for example, bind it to appropriate resources or do 
some more intelligent mapping. There was a suggestion that we allow the 
application to pass an info argument to the init call, allowing it to 
specify what resources it would prefer to be bound to.

  * We finally talked about the MPI progress level query function that 
allows the application to query the MPI implementation about what level 
of progress the MPI implementation provides. The general consensus was 
that the ticket was quite vague at this point and needed more 
description; I'll take care of fixing this, and will be in touch with 
Torsten for feedback.

Thanks,

  -- Pavan

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