Scheduling Complex Cyber-Physical Systems with Mixed-Criticality Components

Abstract

Two emerging trends for designing a complex, cyber-physical systems are the component-based and mixed-criticality (MC) approaches. A component-based approach independently develops individual components and subsequently integrates them to reduce system complexity. This approach provides strong isolation among components but incurs resource inefficiency. Alternatively, an MC approach integrates components of different criticality with different levels of guarantee for resource efficiency, while components are not isolated. To leverage MC and component-based approaches, we investigate how to balance component isolation and resource efficiency under component-based MC systems. We introduce the concept of component-MC schedulability, where isolated tasks are protected from external events outside the component, and shared tasks may be suspended for the critical events of other components. Under component-MC schedulability, we propose a component-based mixed-criticality scheduling framework with dynamic resource allocation (CMC-DRA), which suspends low-criticality tasks differently depending on internal or external component behavior. We also develop scheduling semantics and analyze the schedulability for CMC-DRA. Through simulation on synthetic workloads, we demonstrate that CMC-DRA has up to 88.3% higher schedulability than existing approaches and reduces the deadline miss ratio by up to 47.7%.