Overhead-aware schedulability evaluation of semi-partitioned real-time schedulers

Presented at IEEE 21st International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2015). 19 to 21, Aug, 2015.

Schedulability analyses, while valuable in theo-retical research, cannot be used in practice to reason aboutthe timing behaviour of a real-time system without includingthe overheads induced by the implementation of the schedul-ing algorithm. In this paper, we provide an overhead-awareschedulability analysis based on demand bound functions fortwo hard real-time semi-partitioned algorithms, EDF-WM andC=D. This analysis is based on a novel implementation thatrelies on the use of a global clock to reduce the overheadsincurred due to the release jitter of migrating subtasks. Theanalysis is used to guide the respective off-line task assignmentand splitting procedures. Finally, results of an evaluation areprovided highlighting how the different algorithms performwith and without a consideration of overheads.