Building MPI for Multi-Programming Systems Using Implicit Information

With the growing importance of fast system area networks in the parallel community, it is becoming common for message passing programs to run in multi-programming environments. Competing sequential and parallel jobs can distort the global coordination of communicating processes. In this paper, we describe our implementation of MPI using implicit information for global coscheduling. Our results show that MPI program performance is, indeed, sensitive to local scheduling variations. Further, the integration of implicit co-scheduling with the MPI runtime system achieves robust performance in a multi-programming environment, without compromising performance in dedicated use.