Enabling MPI Interoperability Through Flexible Communication Endpoints

The current MPI model defines a one-to-one relationship between MPI processes and MPI ranks. This model captures many use cases effectively, such as one MPI process per core and one MPI process per node. However, this semantic has limited interoperability be-tween MPI and other programming models that use threads within a node. In this paper, we describe an extension to MPI that introduces communication endpoints as a means to relax the one-to-one rela-tionship between processes and threads. Endpoints enable a greater degree interoperability between MPI and other programming mod-els, and we illustrate their potential for additional performance and computation management benefits through the decoupling of ranks from processes