Dynamic priority scheduling of periodic tasks with extended precedences

The software architecture of a critical embedded control system generally consists of a set of multi-periodic communicating tasks. In order to be able to describe such a system, we define the notion of semaphore precedence constraint, which supports multi-rate communications that follow regular repetitive patterns. We propose a feasibility test for EDF and we study three implementations, for periodic task sets related by such extended precedences on monoprocessor architectures.