Agreed -- specifiying an explicit list of platforms or OS or even resource specifics is not the way to go in a standard.

My suggestion would be to explore if we can define abstract, higher-level resources to define a "state", and specify high-level actions. For instance, pinning/unpinning memory is very specific to RDMA, but maybe a "disconnect virtual connection" operation may abstract it. But this puts us into the realm of virtualizing MPI internal components/concepts ..

Maybe there is a more elegant way ... The thing that worries me is that an MPI implementation may have a fair amount of state sitting on the network card. This state is unreachable by a user- or kernel-level checkpointer but may be reachable by a VMM-level checkpointer. How do we differentiate the level at which we're working? System-level checkpointers working at different levels need MPI state to be flushed to different levels of abstraction and it seems that we'll need to be very low-level in order to define what it means to operate at a given level of abstraction.

Greg Bronevetsky Post-Doctoral Researcher 1028 Building 451 Lawrence Livermore National Lab (925) 424-5756 [email protected]