Characterizing variable task releases and processor capacities
Martin Naedele, Lothar Thiele, Michael Eisenring · 1998
: For the schedulability analysis of hard real-time systems it is important to use task and resource models that appropriately capture the characteristics of the underlying system. In this paper a general task model, the Variable Task Model, most appropriate for tasks with bursty release characteristics, is formalized. Also, a new processor model, the Variable Processor Model, is suggested which allows to account for dead time and variable processing speed. It is shown how worst case bounds on task response time can be calculated. A general schedulability test is derived. Keywords: Tasks, Real-time tasks, Scheduling algorithms 1. INTRODUCTION One of the most important design objectives for hard real-time systems is to obtain a high processor utilisation, while still guaranteeing that all hard deadlines are met. Highly utilizing schedules are only possible, if as much knowledge as possible about the task set and the processor characteristics can be taken into account, while pre...