Dynamic Communicators in MPI...

This paper describes a proposal to add support for dynamic communicators to the MPI standard. This adds the ability to grow or shrink a specified communicator, under well specified circumstances. The goal is to make it possible for a new class of applications – long running, mission-critical, loosely coupled applications, running in a highly dynamic environment - to use MPI libraries for their communications needs, and to enable HPC applications to adjust to changing system resources. Implementation analysis indicates that performance impact on existing high-performance MPI applications should be minimal, or non-existent. The changes to MPI implementations are expected to be well compartmentalized.