Stochastic Modeling and Performance Evaluation of an Event Based System

Event based systems offer decoupling among the communicating entities which provides much needed flexibility for designing large scale distributed and dynamic applications. The constituent entities of these systems are not required to be available at the same time and they can be entirely unaware of each other while providing communication and cooperation among each other. However, this flexibility makes these systems difficult to validate and verify due to inherent non-determinism in which the events are produced, consumed and notified. In this paper, we propose to utilize Performance Evaluation Process Algebra(PEPA) to develop a formal model of an Event Based System. We take a realistic problem for which event based communication style is most suitable. We develop a PEPA model for such system and performed stochastic analysis to reason about the effect of varying number of producers, consumers, event notification services and rates of actions involved. Further, Continuous Stochastic Logic(CSL) is used to verify the proposed model.