EDF-Based Mixed-Criticality Scheduling with Graceful Degradation by Bounded Lateness
Kecheng Yang, Zhishan Guo · 2019
Mixed-criticality (MC) scheduling has been proposed for embedded real-time systems to alleviate the dilemma between runtime resource utilization and worst-case temporal guarantees for critical functions. The approach of dropping all low-criticality tasks upon a mode switch has been criticized for potentially over-degraded performance. In this paper, we focus on the graceful degradation for MC scheduling by providing bounded lateness for certain low-critical tasks. We define MCQOS-schedulability that massages the required bounded lateness into the definition of conventional MC-schedulability. A virtual deadline based scheduler (EDF-VDS) is proposed with utilization-based MCQOS-schedulability test and and closed-form lateness bounds.