Scheduling Real-Time Mixed-Criticality Jobs

Abstract

Abstract. Many safety-critical embedded systems are subject to certification requirements; some systems may be required to meet multiple sets of certification requirements, from different certification authorities. Certification requirements in such "mixed-criticality" systems give rise to interesting scheduling problems, that cannot be satisfactorily addressed using techniques from conventional scheduling theory. In this paper, we study a formal model for representing such mixed-criticality workloads. We demonstrate first the intractability of determining whether a system specified in this model can be scheduled to meet all its certification requirements, even for systems subject to two sets of certification requirements. Then we quantify, via the metric of processor speedup factor, the effectiveness of two techniques, reservation-based scheduling and priority-based scheduling, that are widely used in scheduling such mixedcriticality systems, showing that the latter of the two is superior to the former. We also show that the speedup factors are tight for these two techniques.

Outstanding Paper Award: Bounding and Shaping the Demand of Mixed-Criticality Sporadic Tasks

“…Response-time analysis for fixed-priority scheduling has since been improved by Baruah et al. [4] A number of papers have considered the more restricted problem of scheduling a finite set of mixed-criticality jobs (e.g., [5], [6]). Baruah et al have shown that the problem of deciding whether a given set of jobs is schedulable by an optimal scheduling algorithm is NP-hard in the strong sense [6].…”

“…[4] A number of papers have considered the more restricted problem of scheduling a finite set of mixed-criticality jobs (e.g., [5], [6]). Baruah et al have shown that the problem of deciding whether a given set of jobs is schedulable by an optimal scheduling algorithm is NP-hard in the strong sense [6]. Work on mixed-criticality scheduling has since been focused on finding scheduling strategies that, while being suboptimal, still work well in practice.…”

Stretch: exploiting service level degradation for energy management in mixed-criticality systems

“…importance) into a common and shared computing platform [1]- [7]. Therefore, mixed-criticality systems are considered to be the next generation of complex embedded systems [1], [8]- [10]. Hence, they have lately become the subject of vast researches considering improvements in Cyber-Physical Systems (CPS) [8], [11].…”

“…Therefore, based on different criticality levels, varying degree of assurance should be provided for mixed-criticality systems [7], [12], [13]. Recently, two different approaches have been considered upon mixed-criticality systems [1]. The obvious one is treating criticality as priority of tasks in scheduling algorithms, hence employing priority-based scheduling mechanisms.…”

“…importance) into a common and shared computing platform [1]- [7]. Therefore, mixed-criticality systems are considered to be the next generation of complex embedded systems [1], [8]- [10].…”