Author:

Keywords:

Coordination, Software connectors, Reo, Distributed systems, Visual formalisms, Animations, Constraint satisfaction, Connector colouring, Constraint automata, Actor model

Abstract:

This work contributes to the field of coordination, in particular to Reo, by improving existing approaches to execute synchronisation models in three major ways. First, this work supports decoupled execution and lightweight reconfiguration. We developed a prototype Dreams engine to test our distributed protocol, using an actor library for the Scala language. Reconfiguration of a small part of the system is independent of the execution or behaviour of unrelated parts of the same system. Second, Dreams outperforms previous Reo engines by using constraint satisfaction techniques. In each round of the execution of the Dreams framework, descriptions of the behaviour of all building blocks are combined and a coordination pattern for the current round is chosen using constraint satisfaction techniques. This approach requiring less time than previous attempts that collect all patterns before selecting one. Third, our work improves scalability by identifying synchronous regions. We statically discover regions of the coordination layer that can execute independently, thus achieving a truly decoupled execution of connectors. Consequently, the constraint problem representing the behaviour at each round is smaller and more easily solved.