Criticality-Aware EDF Scheduling for Constrained-Deadline Imprecise Mixed-Criticality Systems

EDF-VD first focuses on the classic mixed-criticality task model in which all low-criticality (LO) tasks are abandoned in the high-criticality mode, which is an effective dynamic priority scheduling algorithm for mixed-criticality systems. However, it has low schedulability for the imprecise mixed-criticality (IMC) task model with constrained deadlines, in which LO tasks are provided graceful degradation services instead of being abandoned. In this article, we study how to improve schedulability for the IMC tasks model. First, we propose a novel criticalityaware EDF scheduling algorithm (CA-EDF) that tries to delay the LO task execution to improve schedulability. Second, we derive sufficient conditions of schedulability for CA-EDF based on the Demand Bound Function. Finally, we evaluate CA-EDF through extensive simulation. The experimental results indicate that CA-EDF can improve the schedulability ratio by about 13.10% compared to the existing algorithms.