Response time analysis of asynchronous real-time systems

In asynchronous real-time systems the time when all events occur can not be predicted beforehand. Systems with sporadic tasks, or that operate a protocol for sharing resources like the priority ceiling protocol, for example, are asynchronous real-time systems. In this paper, we present a sufficient and efficient response time based analysis technique for computing R-i(k), the worst case response time at each invocation k of the periodic tasks of real-time asynchronous systems. In addition, efficient idle time computation for asynchronous systems is presented. This analysis technique can be applied to the analysis of several process models including weakly hard real-time systems, and slack management techniques like aperiodic servers and slack stealing algorithms. It is also show that the pattern of response times of tasks in a hyperperiod is pseudoperiodic and that the maximum response time instants tend to occur evenly separated within the hyperperiod.