Efficient Discrete-Event Simulation of Colored Petri Nets

Colored Petri nets are a powerful formalism for the description of complex, asynchronous distributed systems. They can express in a very concise way the behavior of very large systems, especially in case these systems are composed of many replications of a few basic components that individually behave in a similar way. The simulation of such models is, however, difficult to perform in a computationally efficient way. For the specific class of stochastic well-formed nets (SWNs), we present a set of optimizations that allow a very efficient implementation of the event-driven simulation technique. Three approaches are followed to improve simulation efficiency: first, an efficient algorithm for the computation of the occurrences of a transition in a given marking; second, reduction of the amount of work needed to schedule or preempt the occurrence of a transition as a consequence of a marking change, taking into account the restrictions on color functions for the SWN formalism; third, reduction of the average length of the event list in the case of symmetric models where the so-called symbolic simulation technique applies. The approach is validated by performance measurements on several large SWN models taken from the literature.