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

Abstract

We derive demand-bound functions for mixed-criticality sporadic tasks, and use these to determine EDF-schedulability. Tasks have different demand-bound functions for each criticality mode. We show how to shift execution demand from high-to low-criticality mode by tuning the relative deadlines. This allows us to shape the demand characteristics of each task. We propose an efficient algorithm for tuning all relative deadlines of a task set in order to shape the total demand to the available supply of the computing platform. Experiments indicate that this approach is significantly more powerful than previous approaches to mixed-criticality scheduling. This new approach has the added benefit of supporting hierarchical scheduling frameworks.