Consistency Challenges in Self-Organizing Distributed Hard Real-Time Systems

Allowing real-time systems to autonomously evolve or self-organize during their life-time poses challenges on guidance of such a process. Hard real-time systems must never break their timing constraints even if undergoing a change in configuration. We propose to enhance future real-time systems with an in-system model-based timing analysis engine capable of deciding whether a configuration is feasible to be executed. This engine is complemented by a formal procedure guiding system evolution. The distributed implementation of a runtime environment (RTE) implementing this procedure imposes two key questions of consistency: How do we ensure model consistency across the distributed system and how do we ensure consistency of the actual system behavior with the model? We present a synchronization protocol solving the model consistency issues and provide a discussion on implications of different mode-change protocols on consistency of the system with its model.