Real-time scheduling of non-preemptive sporadic tasks on uniprocessor systems using Supervisory Control of timed DES

Abstract

Scheduling strategies for non-preemptive real-time tasks on uniprocessors typically attempt to derive necessary and sufficient schedulability conditions in order to guarantee the timely execution of tasks. However, evaluating all conditions to allow the optimal scheduling of non-preemptive tasks is intractable, and is prohibitively expensive to be applied online. Therefore, on-line approaches, which often do not allow the liberty of exhaustive enumeration of the solution space, tend to be sub-optimal and heuristic in nature. Hence, off-line techniques are often preferred over on-line techniques for solving such problems. Among the existing off-line techniques, formal approaches are the preferred choice due to their ability to guarantee correctness and completeness. Using Supervisory Control Theory (SCT) of Timed Discrete Event Systems (TDESs) as the underlying formal approach, this work proposes an off-line optimal scheduler synthesis framework for non-preemptive sporadic real-time tasks on uniprocessors.