Unsynchronized parallel discrete event simulation

Distributed synchronization for parallel simulation is generally classified as being either optimistic or conservative. While considerable investigations have been conducted to analyze and optimize each of these synchronization strategies, very little study on the definition and strictness of causality have been conducted. Do we really need to preserve causality in all types of simulations? The paper attempts to answer this question. We argue that significant performance gains can be made by reconsidering this definition to decide if the parallel simulation needs to preserve causality. We investigate the feasibility of unsynchronized parallel simulation through the use of several queuing model simulations and present a comparative analysis between unsynchronized and Time Warp simulation.