So I didn't catch everything that went on because clearly Keith was referring to things projected from his laptop but not enumerated out loud. That, and 7-9 PM is usually beer-time not RMA-time in my house. On the issue of "should MPI-3 support X (with performance)?" where X={ARMCI,GASNet,etc.}, I think it is quite clear than MPI-3 RMA should meet the criteria of implementing ARMCI RMA, either as ARMCI on top of MPI-3 of GA on top of MPI-3 (replacing ARMCI altogether). The distinction between the latter two choices is mostly irrelevant; ARMCI over MPI-3 can be pretty close to an #define implementation rather than an abstraction layer which affects performance. I suspect that on some platforms, ARMCI may still be required to achieve optimal performance for strided accumulate etc., but for leadership-class machines with RDMA or otherwise powerful NICs, ARMCI will be nothing more than syntactic sugar to make GA portable. This fact has been clearly demonstrated by the DCMF port of ARMCI, which completely bypasses the ARMCI data server but compensates with low-level communication-helper-thread support. Although I don't doubt that user-defined accumulate provides a mechanism for active-messaging (AM) capability, I do not fully subscribe to the notion - sorry Pavan - that MPI-3 accumulate is sufficient to implement GASNet if performance is a consideration. I sincerely hope that the Forum follows through on the AM working group and produces a real AM interface that competes on all levels with GASNet. Keith is right that GASNet's direct targeting of low-level AM functionality will preclude MPI-3 from ever being a performance-oriented compromise. However, it is useful to have MPI-3 as a portable fall-back for implementing AM via user-defined accumulate. Best, Jeff On Tue, Mar 9, 2010 at 6:32 PM, Jeff Hammond <[email protected]> wrote:

...

Tuesday: 4.15-7.00pm Pacific Tel: (866) 432-9903 �OR �(408) 525-6800 Meeting Number: 200 438 253

Is this happening? �I called in but no one else is on.

Thanks,

Jeff

-- Jeff Hammond Argonne Leadership Computing Facility [email protected] / (630) 252-5381 http://www.linkedin.com/in/jeffhammond

-- Jeff Hammond Argonne Leadership Computing Facility [email protected] / (630) 252-5381 http://www.linkedin.com/in/jeffhammond