Shray: An Owner-Compute Distributed Shared-Memory System

In this paper, we propose a new library for storing arrays in a distributed fashion on distributed memory systems. From a programmer's perspective, these arrays behave for arbitrary reads as if they were allocated in shared memory. When it comes to writes into these arrays, the programmer has to ensure that all writes are restricted to a fixed range of address that are "owned" by the node executing the writing operation. We show how this design, despite the owner-compute restriction can aid programmer productivity by enabling straight-forward parallelisations of typical array-manipulating codes. Furthermore, we delineate an open-source implementation of the proposed library named Shray. Using the programming interface of Shray, we compare possible hand-parallelised codes of example applications with implementations in other DSM/PGAS systems demonstrating the programming style enabled by Shray, and providing some initial performance figures.