On the Synchronization Mechanisms in Distributed Shared Memory Systems

Distributed Shared Memory (DSM) is the implementation of the shared memory programming paradigm on a distributed memory (or multicomputer) system. Programming multicomputer systems using Distributed Shared Memory as the programming model is appealing because it combines the performance advantage of distributed memory systems and the ease of programming of shared memory systems. In DSM systems, cooperating tasks communicate with one another through shared variables. Thus, DSM systems must provide synchronization mechanisms to Coordinate concurrent access to these shared variables. In this paper we describe and classify the synchronization mechanisms supported by several Distributed Shared Memory systems. We classify these systems according to whether they are hardware or software based, whether the mechanism is integrated into the system or not and whether implementation of the synchronization mechanism is centralized or distributed.