An Integrated Runtime Scheduler for MPI

Abstract. Fine-Grain MPI (FG-MPI) supports function-level parallelism while staying within the MPI process model. It provides a runtime that is directly integrated into the MPICH2 middleware and uses lightweight coroutines to implement an MPI-aware scheduler. Our key observation is that having multiple MPI processes per OS-process, with a runtime scheduler can be used to simplify MPI programming and achieve performance without adding complexity to the program. The performance part of the program is now outside of the specification of the program in the runtime where performance can be tuned with few, if any, changes to the code