Specification-based Verification in a Distributed Shared Memory Simulation Model

Abstract

The emergence of chip multiprocessors is leading to rapid advances in hardware and software systems to provide distributed shared memory (DSM) programming models, so-called DSM systems. A DSM system provides programming advantages within a scalable and cost-effective hardware solution. This benefit derives from the fact that a DSM system creates a shared-memory abstraction on top of a distributed-memory machine by caching data replicas locally. In this respect, a coherence protocol is a vital component responsible for assuring data consistency across all replicas. The design of coherence protocols impacts a DSM system in terms of both performance and accuracy. Performance is often measured via simulation and various verification techniques have been proposed to deal with protocol accuracy. Nevertheless, integrating accuracy verification into a DSM cluster simulation to ensure correct simulation results is still an open issue. In this paper, we address three properties of a coherence protocol (safety, liveness, and inclusion) without which errors may occur in the simulation results. We propose a specification-based parameter—model interaction (SPMI) technique to detect these cases in a particular DSM cluster simulator called DSiMCluster. Our experimental results demonstrate that with SPMI, DSiMCluster can ensure the coherence protocol properties and provides a correct reflection of memory characteristics in shared-memory and DSM multiprocessors.