Integration of resource synchronization and preemption-thresholds into EDF-based mixed-criticality scheduling algorithm

In mixed-criticality systems, multiple subsystems with different levels of criticality may co-exist on the same hardware platform. Many scheduling algorithms have been proposed to achieve certification at multiple levels of criticality. However, current MCS algorithms and analysis techniques generally assume tasks are independent, i.e., they do not share data that need to be protected with synchronization mechanisms like mutexes or semaphores. In this paper, we address this limitation by presenting an extension to the Stack Resource Protocol (SRP), called Mixed-Criticality-SRP (MC-SRP). Moreover, preemption-threshold scheduling is a well-known technique for reducing stack space size and enhance schedulability in resource-constrained embedded systems.We also present the integration of preemption-thresholds into EDF-based mixed-criticality scheduling (MCS) algorithms, and develop the schedulability analysis methods to such systems.