An improved rate-monotonic admission control and its applications

Rate-monotonic scheduling (RMS) is a widely used real-time scheduling technique. This paper proposes RBound, a new admission control for RMS. RBound has two interesting properties. First, it achieves high processor utilization under certain conditions. We show how to obtain these conditions in a multiprocessor environment and propose a multiprocessor scheduling algorithm that achieves a near optimal processor utilization. Second, the framework developed for RBound remains close to the original RMS framework (that is, task dispatching is still done via a fixed-priority scheme based on the task periods). In particular, we show how RBound can be used to guarantee a timely recovery in the presence of faults and still achieve high processor utilization. We also show how RBound can be used to increase the processor utilization when aperiodic tasks are serviced by a priority exchange server or a deferrable server.