Polyhedral Scheduling and Relaxation of Synchronous Reactive Systems

International audienceThe design and implementation of reactive, hard real-time systems involves modeling and generating efficient code for the integration of harmonic multi-periodic tasks. The simple principles of synchronous reactive programming met great scientific and engineering success in the area. A synchronous program orchestrates concurrent computations. It does so while maintaining composability, modularity, functional determinism and real-time execution guarantees. In the case of hard real-time systems, a reactive control program is composed of multi-periodic tasks related through integral ratios. This paper presents a language and optimizing compiler to implement large reactive control systems composed of multi-periodic, synchronous reactive tasks. The same language is used to program a complete control system, from the finest-grained computations to task-level integration, while generating efficient code satisfying real-time constraints. It is evaluated on two real-world applications