It's obviously a bit too late for MPI-3, but it might be a useful exercise to make sure that MPI-3.0 RMA is sufficient for the GCC CAF runtime (http://gcc.gnu.org/wiki/CoarrayLib). It seems that it is though since they seem to support or attempt to support ARMCI, which we know is compatible with MPI-2.2 RMA. I know that GCC PGAS implementers are interested in MPI-3, if for no other reason than neither GASNet nor ARMCI is an RPM in any Linux distro of which I am aware. Best, Jeff -- Jeff Hammond Argonne Leadership Computing Facility University of Chicago Computation Institute [email protected] / (630) 252-5381 http://www.linkedin.com/in/jeffhammond https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond