An OpenSHMEM Runtime for UPC

Abstract

Partitioned Global Address Space (PGAS) languages are becoming more important aswe move into the Exascale era. The complexities brought on by the architectures of thesemachines make traditional message passing approaches challenging. Currently, we lack aportable and flexible runtime for PGAS languages. The suggestion is that this is possiblewith an OpenSHMEM-based runtime. OpenSHMEM is a PGAS library for the C language aiming to provide a standardApplication Programming Interface (API) for Symmetric Hierarchical MEMory (SHMEM).OpenSHMEM is a portable, flexible, and performant API for PGAS runtimes throughits use of thread safety semantics and grouping of processes through teams. This allowsOpenSHMEM to make performance-oriented decisions on behalf of the language or librarybeing implemented. This thesis demonstrates a mapping and implementation of a Unified Parallel C (UPC)runtime based on OpenSHMEM, and an evaluation our runtime’s performance in comparisonto the popular Berkeley UPC implementation. Berkeley UPC uses a runtime based onGlobal-Address Space Networking (GASNet), a language independent middleware forPGAS programming languages.