Uniprocessor-Independent Task Scheduling

Abstract

Scheduling is the process of assigning tasks to a processor or a set of processors as in the case of a multiprocessor system or to a network of computing elements when a distributed real-time system is considered. A real-time task has a release time, execution time, a deadline, and resource requirements. A periodic task is activated at regular intervals, an aperiodic task may be activated at any time, and a sporadic task has a minimum interval between any of its consecutive activations. Tasks may have precedence relation among them which means a task cannot start before its predecessors complete. Moreover, tasks may be sharing resources which affect scheduling decisions. Our main goal in scheduling real-time tasks is to have tasks meet their deadlines and fair sharing of resources. We describe uniprocessor-independent task scheduling in this chapter.