Design and analysis of semaphore precedence constraints: A model-based approach for deterministic communications

Architecture Analysis and Design Language (AADL) is a standard in avionics system design. However, the communication patterns provided by AADL are not sufficient to the current context of Real-Time Embedded System (RTES) in which some multi-periodic communication patterns may occur. We propose an extension of a precedence model between tasks of different periods (multiperiodic communication). This relies on the Semaphore Precedence Constraint (SPC) model that is inspired from the concept of Semaphore, and more specifically on the m-n producer/consumer paradigm. We reinforce the SPC semantics by allowing cycles in the SPC precedence graph. We also present another viewpoint on the periodicity of tasks system using SPC based on a graph apart from the encoding technique presented in the SPC seminal work. An implementation of SPC in AADL and its associated analysis tool are also provided to study the temporal behaviour of systems using SPC.