Improving and modeling the performance of a Publish-Subscribe message broker

The Event Handler – a publish-subscribe broker implemented over REST/HTTP(S) – is an auxiliary system of the Arrowhead framework for IoT applications. During this work we found that the existing implementation of the Event Handler suffers from serious performance issues. This paper describes the reengineering effort that ultimately enabled it to reach much more acceptable levels of performance, by using appropriate software configurations and design patterns. Additionally, we also illustrate how this enhanced version of the Event Handler can be modeled using Petri nets, to depict the performance impact of different thread pool configurations and CPU core availability. The main objective of this modeling process is to enable the estimation of the system’s performance to guarantee the required quality of service.