Performance Models of Event-Driven Architectures

Event-driven architecture (EDAs) improves scalability by combining stateless servers and asynchronous interactions. Models to predict the performance of pure EDA systems are relatively easy to make, systems with a combination of event-driven components and legacy components with blocking service requests (synchronous interactions) require special treatment. Layered queueing was developed for such systems, and this work describes a method for combining event-driven behaviour and synchronous behaviour in a layered queueing model. The performance constraints created by the legacy components can be explored to guide decisions regarding converting them, or reconfiguring them, when the system is scaled.