Breathing Time Warp

Time Warp and Breathing Time Buckets are two general-purpose optimistic synchronization strategies for supporting parallel discrete-event simulations. However, each one of these approaches has potential fatal shortcomings. Time Warp may exhibit rollback explosions that can cause an avalance of antimessages. Breathing Time Buckets, on the other hand, may not be able to process enough events per synchronization cycle to remain efficient. A new strategy, called Breathing Time Warp, has been developed in the Synchronous Parallel Environment for Emulation and Discrete-Event Simulation (SPEEDES) operating sytem. This new strategy solves both of these problems by mixing the two algorithms together, resulting in the best of both methods. This paper describes the implementation of the Breathing Time Warp algorithm in SPEEDES, and then shows how this new approach sometimes improves the performance of parallel discrete-event simulations.