On Critical Path Analysis of Parallel Discrete Event Simulations

Several protocols have been proposed to synchronize the logical processes (LP’s) of a parallel discrete event simulation (PDES). While most protocols have been known to perform well under certain conditions, the general observation has been that the performance of protocols is sensitive to the application being simulated, sometimes even to a particular instance of it. In this technical note, we address the issue of determining a lower bound on the completion time of a particular simulation run using critical path analysis. Two studies have been conducted previously on this subject. While these studies have provided some useful insights into the performance of protocols, certain issues have remained unexplored. We examine these issues and present four enhancements to the earlier results one of which is to indicate a flaw in one of the previous studies. The two main contributions of this work are to present: (i) a trivial lower bound for all PDES’s which contradicts a result from one of the previous studies and, (ii) a reasonable lower bound on the completion time for all PDES’s.