Investigating concurrency in the co-simulation orchestration engine for INTO-CPS

The development of Cyber-Physical Systems often involves cyber elements controlling physical entities, and this interaction is challenging because of the multi-disciplinary nature of such systems. It can be useful to create models of the constituent components and simulate these in what is called a co-simulation, as it can help to identify undesired behaviour. The Functional Mock-up Interface describes a tool-independent standard for constituent components participating in such a co-simulation and can support different formalisms. This paper describes an exploration of whether different concurrency features in Scala (actors, parallel collections, and futures) increase the performance of an existing application called the Co-Simulation Orchestration Engine performing co-simulations. The investigation was conducted by refactoring the existing application to make it suitable for implementing functionality that takes advantage of the concurrency features. In order to compare the different implementations testing was carried out using four test co-simulations. These test co-simulations were executed using the concurrent implementations and the original sequential implementation, verifying the simulation results, and retrieving the execution times of the simulations. The analysis showed that concurrency can be used to increase the performance in terms of execution time in some cases, but in order to achieve optimal performance, it is necessary to combine different strategies. Based on these results, future work tasks has been proposed.