Schedulability Analysis of Synchronous Digraph Real-Time Tasks

Real-time task models have evolved from periodic models to more sophisticated graph-based ones like the Digraph Real Time task model (DRT) to specify branching and loop structures of real-time embedded software. For independent DRT tasks, efficient techniques for schedulability analysis have been developed in previous work. In this paper, we extend the DRT model to specify inter-task synchronization through a rendezvous mechanism. We present an abstraction technique for static priority schedulability analysis of the corresponding tasks. Our experiments show that, despite the high computational complexity of the problem, the proposed technique scales very well for large sets of dependent tasks.