[mpi3-coll] Telecon Notes

[Torsten Hoefler]

Hi,
here are my notes on today's telecon:

** Attendees (alphabetically):
- Greg Bronevetsky (LLNL)
- Torsten Hoefler (IU)
- Jesper Larsson Traff (NEC)
- Andrew Lumsdaine (IU)
- Amith Mamidala (OSU)
- Adam Moody (LLNL)
- Rolf VandeVaart (Sun)

** Disucussions (cf. Agenda):
1) Jesper: step back, should NBC be in the standard at all? Why not
  modularize it?
- Andrew: pro standardization
-- portability is higher for standardized things
-- people won't use them
-- higher performance if it is in the library
- Torsten: we have an implementation for NBC
  (http://www.unixer.de/research/nbcoll/libnbc/), BSD license (can be
  packaged with MPI)
- Torsten: it's confusing to have NBC as a separate library and blocking
  colls not (see sent mails)
- Torsten: have a more modularized standard
a) Jesper and Torsten agree to have no tags - no further discussion
b) allow multiple outstanding requests
c) Torsten: MPI Forum approach does not work
   Greg: it could be optimized (putting threads to sleep) but it will
   still be slow and horrible to program
d) Torsten, Andrew: no matching necessary
   Jesper: no matching possible in the standard
e) Torsten: no request free/cancel
   Andrew: there might be a situation (loosely coupled apps)
   Torsten: look at and understand p2p issues first
   Greg: Fault Tolerance?
f) Torsten: don't change anything, stick with the old way

3) Jesper: proposed approach is too limited
b) Torsten: merge with 4)
c) Jesper has a paper about this on IPDPS

4) IU goes off and proposes better ideas, Jesper wants to join

5) Jesper writes proposal-like document

6) contact mpi3-subsetting and see what they think

general things:
- next meeting in March in Chicago
- have proposals ready at leat one week before meeting in March
- contact more application people (forward to Torsten)
- contact Asian researchers (Jesper?)

The full recording (68:43) is available for private use (contact me).

Best,
  Torsten

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