Parallelising symbolic state-space generators

Abstract

Symbolic state-space generators are notoriously hard to parallelise, largely due to the irregular nature of the task. Parallel languages such as CiIk, tailored to irregular problems, have been shown to offer efficient scheduling and load balancing. This paper explores whether Cilk can be used to efficiently parallelise a symbolic state-space generator on a shared-memory architecture. We parallelise the Saturation algorithm implemented in the SMART verification tool using Cilk, and compare it to a parallel implementation of the algorithm using a thread pool. Our experimental studies on a dual-processor, dual-core PC show that Cilk can improve the run-time efficiency of our parallel algorithm due to its load balancing and scheduling efficiency. We also demonstrate that this incurs a significant memory overhead due to Cilk's inability to support pipelining, and conclude by pointing to a possible future direction for parallel irregular languages to include pipelining. © Springer-Verlag Berlin Heidelberg 2007.