Introducing cray OpenSHMEMX - A modular multi-communication layer OpenSHMEM Implementation

Abstract

SHMEM has a long history as a parallel programming model. It is extensively used since 1993, starting from Cray T3D systems. For the past two decades SHMEM library implementation in Cray systems evolved through different generations. The current generation of the SHMEM implementation for Cray XC and XK systems is called Cray SHMEM. It is a proprietary SHMEM implementation from Cray Inc. In this work, we provide an in-depth analysis of need for a new SHMEM implementation and then introduce the next evolution of Cray SHMEM implementation for current and future generation Cray systems. We call this new implementation Cray OpenSHMEMX. We provide brief design overview, along with a review of functional and performance differences in Cray OpenSHMEMX comparing against the existing Cray SHMEM implementation.