Implementing the Open Community Runtime for Shared-Memory and Distributed-Memory Systems

The extreme scale, complexity and performance variability of future high performance computing systems pose many new challenges to parallel programming models and runtime systems. The Open Community Runtime (OCR) is a recent effort for a task-based runtime system for extreme scale parallel systems. We have implemented the OCR specification in a shared-memory environment on top of TBB, providing an alternative to the implementation created by the OCR consortium. We have created an experimental extension that supports parallel accelerators programmed with OpenCL. We also have an implementation that targets distributed-memory systems. Despite being in an early stage of development, our implementations can achieve reasonable performance with some applications. We describe the main aspects of our OCR implementations and report on early experimental results on shared-memory and distributed-memory systems.