This paper presents an analysis on the performance of a parallel implementation of a discrete model of laser dynamics, which is based on cellular automata. The performance of a 2D parallel version of the model is studied as a first step to test the feasibility of a parallel 3D version, which is needed to simulate specific laser systems. The 3D version will have to run on a parallel computer due to its runtime and memory requirements. The model has been implemented on a Beowulf Cluster using the message passing paradigm. The parallel implementation is found to exhibit a good speedup, allowing us to run realistic simulations of laser systems on clusters of workstations, which could not be afforded on an individual machine due to the extensive runtime and memory size needed.