[Mpi3-hybridpm] Draft of hybrid prog models group goals

[Rajeev Thakur]

All working groups are supposed to come up with a set of goals for the
group (i.e., what is the group's mission?). Below is a draft of goals
for the hybrid programming models group. It is intended as a starting
point for discussion. Please suggest changes as appropriate.

Rajeev 


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Parallel computers are increasingly being built with nodes comprising
large numbers of cores that include regular CPUs as well as accelerators
such as Cell or GPUs. To make better use of shared memory and other
resources within a node or address space, users may want to use a hybrid
programming model that uses MPI for communicating between nodes or
address spaces and some other programming model (X) within the node or
address space. Various options for X at present include OpenMP,
Pthreads, PGAS languages (UPC, CoArray Fortran), Intel TBB, Cilk, CUDA,
and OpenCL. The goal of this working group is to ensure that MPI has the
features necessary to facilitate efficient hybrid programming.

Specifically, the group will investigate:

* What changes are needed in MPI to better support threads (Pthreads,
OpenMP)? 

* What changes are needed in MPI to better support MPI+OpenCL or
MPI+CUDA programs?

* What changes are needed in MPI to better support MPI+UPC or MPI+CAF
programs?

* (Other hybrid models as appropriate.)