An Open Standard for SHMEM Implementations Introduction

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OpenSHMEM: An Open Standard for SHMEM Implementations Introduction • OpenSHMEM is an effort to create a standardized SHMEM library for C , C++, and Fortran • OpenSHMEM is a Partitioned Global Address Space (PGAS) library and supports Single Program Multiple Data (SPMD) style of programming • SGI’s SHMEM API is the baseline for OpenSHMEM Specification 1.0 • One-sided communication is achieved through Symmetric variables • globals C/C++: Non-stack variables Fortran: objects in common blocks or with the SAVE attribute • dynamically allocated and managed by the OpenSHMEM Library Figure 1. Dynamic allocation of symmetric variable ‘x’ OpenSHMEM API • OpenSHMEM Specification 1.0 provides support for data transfer operations, collective and point- to-point synchronization mechanisms (barrier, fence, quiet, wait), collective operations (broadcast, collection, reduction), atomic memory operations (swap, fetch/add, increment), and distributed locks. • Open to the community for reviews and contributions. Current Status • University of Houston has developed a portable reference OpenSHMEM library. • OpenSHMEM Specification 1.0 man pages are available. • OpenSHMEM mailing list for discussions and contributions can be joined by emailing [email protected] • Website for OpenSHMEM and a Wiki for community use are available. Figure 2. University of Houston http://www.openshmem.org/ Implementation Future Work and Goals • Develop OpenSHMEM Specification 2.0 with co-operation and contribution from the OpenSHMEM community • Discuss and extend specification with important new capabilities • Improve on the OpenSHMEM reference implementation by providing support for scalable collective algorithms • Explore innovative hardware platforms .

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