Approaches for Multi-Core Propagation in Clause Learning Satisfiability Solvers

Parallelization of unit propagation in SAT solvers is a compelling way of obtaining an efficient parallel decision procedure for the propositional satisfiability problem. However, due to the P-completeness of unit propagation, it is challenging to achieve good efficiency in practice. In this article, we present two methods for unit propagation on multi-core systems and their implementation. We throughly evaluate these techniques by comparison to a simulation that estimates a baseline efficiency and by experimental evaluation of an implementation on competition benchmarks. We thereby demonstrate that achieving a speed-up linear in the number of cores is indeed challenging in practice, but also that unit propagation on multi-core systems is feasible in practice.