Enhanced Support for OpenSHMEM Communication in Portals

The looming challenges of exascale computing are generating renewed interest in the Partitioned Global Address Space (PGAS) parallel programming model. From a high-performance interconnect perspective, the one-sided communication model in PGAS addresses some of the challenges that could inhibit the viability of traditional two-sided MPI message passing on millions of cores. The OpenSHMEM project is a recent effort at standardizing a lightweight one-sided communication interface to enable the development of highly scalable PGAS applications. The Portals data movement layer is a low-level one-sided interface that has successfully supported several higher-level one-sided and two-sided interfaces, including PGAS network transport layers. This paper describes the design and implementation of OpenSHMEM on the latest generation of the Portals interface, including a description of how Portals has evolved to maximize performance for PGAS-style communication operations.