OpenSHMEM Extensions and a Vision for Its Future Direction

The Extreme Scale Systems Center (ESSC) at Oak Ridge National Laboratory (ORNL), together with the University of Houston, led the effort to standardize the SHMEM API with input from the vendors and user community. In 2012, OpenSHMEM specification 1.0 was finalized and released to the OpenSHMEM community for comments. As we move to future HPC systems, there are several shortcomings in the current specification that we need to address to ensure scalability, higher degrees of concurrency, locality, thread safety, fault-tolerance, parallel I/O capabilities, etc. In this paper we discuss an immediate set of extensions that we propose to the current API and our vision for a future API, OpenSHMEM Next-Generation (NG), that targets future Exascale systems. We also explain our rational for the proposed extensions and highlight the lessons learned from other PGAS languages and communication libraries.