Overhead-Aware Study of Hierarchical Fixed Priority Preemptive Systems
Jorge Luis Martinez Garcia, Ignacio Sanudo Olmedo, Dakshina Dasari, Arne Hamann · 2021
Real-time servers have been widely explored in the scheduling literature to predictably execute aperiodic activities, as well as to allow hierarchical scheduling settings. As they allow achieving timing isolation between previously isolated and functionally diverse applications, there is a renewed interest for the adoption of fixed priority real-time servers in the automotive domain, as a way to implement more efficient reservation mechanisms than TDMA-based methods. Thus, this paper presents an overhead-aware schedulability analysis for hierarchical fixed priority preemptive (HFPP) systems, and proposes a practical server parameterization technique preserving the least possible utilization and enhancing the aggregated WCRT, i.e. the sum of WCRTs, of the tasks in a hierarchical scheduling setting.