Toward transparent selective sequential consistency in distributed shared memory systems

This paper proposes a transparent selective sequential consistency approach to distributed shared memory (DSM) systems. First, three basic techniques-time selection, processor selection, and data selection-are analyzed for improving the performance of strictly sequential consistency DSM systems, and a transparent approach to achieving these selections is proposed. Then, this paper focuses on the protocols and techniques devised to achieve transparent data selection, including a novel selective lazy/eager updates propagation protocol for propagating updates on shared data objects, and the critical region updated pages set scheme to automatically detect the associations between shared data objects and synchronization objects. The proposed approach is able to offer the same potential performance advantages as the entry consistency model or the scope consistency model, but it imposes no extra burden to programmers and never fails to execute programs correctly. The devised protocols and techniques have been implemented and experimented with in the context of the TreadMarks DSM system. Performance results have shown that for many applications, our transparent data selection approach outperforms the lazy release consistency model using a lazy or eager updates propagation protocol.