Mapping hierarchical, modular discrete event models in a hypercube multicomputer

Abstract

The Discrete Event Systems Specification (DEVS) formalism specifies discrete event systems in a modular, hierarchical form. Timed state transitions within the formalism are specified by an external transition function for randomly arriving external events. The internal transition function schedules internal events. This paper devises a mapping algorithm which exploits a maximum degree of parallelism in DEVS simulation. For parallel DEVS simulation, some hierarchical simulation algorithms were already developed. However, our mapping algorithm employs different approaches for parallelizing the two types of events. For external events parallelization, a task graph representing a hierarchical DEVS model is transformed into a binomial tree which can be easily embedded into a hypercube network. The transformation markedly reduces the synchronization overhead for parallel computation. For internal events parallelization, a hypercube is partitioned into a set of subcubes such that an internal event, and the external events caused by the internal event are processed in the same subcube. Simulation experimentations with a simple benchmark model show that the potential parallelism of DEVS simulation can be exploited by using the proposed algorithm.