Priority-based scheduling of mixed-critical jobs

Abstract

Modern real-time systems tend to be mixed-critical, in the sense that they integrate on the same computational platform applications at different levels of criticality (e.g., safety critical and mission critical). Scheduling of such systems is a popular topic in literature due to the complexity and importance of the problem. In this paper we propose two algorithms for job scheduling in mixed critical systems: mixed criticality earliest deadline first (MCEDF) and mixed critical priority improvement (MCPI). MCEDF is a single processor algorithm that theoretically dominates state-of-the-art fixed-priority algorithm own criticality based priority (OCBP), while having a better computational complexity. The dominance is achieved by profiting from a common extension of fixed-priority online policy to mixed criticality. MCPI is a multiprocessor algorithm that supports dependency constraints. Experiments show good schedulability results. Also we formally prove that both MCEDF and MCPI are optimal in a particular class of algorithms.