A Performance Evaluation of the Lightweight Time Warp Protocol in Optimistic Parallel Simulation of DEVS-Based Environmental Models

The lightweight time warp (LTW) protocol offers a novel approach to high-performance optimistic parallel discrete-event simulation, especially when a large number of simultaneous events need to be executed at each virtual time. With LTW, the local simulation space on each node is partitioned into two sub-domains, allowing purely optimistic simulation to be driven by only a few full-fledged logical processes (LPs), while most processes are turned into lightweight LPs, free from the burden associated with time warp (TW) execution. This paper presents a comparative performance evaluation of the TW and LTW protocols for simulating several DEVS-based environmental models. The experiments indicate that the LTW protocol improves performance in terms of shortened execution time, reduced memory usage, lowered operational cost, and enhanced system stability.