GUARANTEEING REAL-TIME REQUIREMENTS WITH RESOURCE-BASED CALIBRATION OF PERIODIC PROCESSES

This paper presents a comprehensive design methodology for guaranteein g end-to-end requirements of real-time systems. Applications are struc tured as a set of process components connected by asynchronous channel s, in which the end-points are the system's external inputs and output s. Timing constraints are then postulated between these inputs and out puts; they express properties such as end-to-end propagation delay, te mporal input-sampling correlation, and allowable separation times betw een updated output values. The automated design method works as follow s: First new tasks are created to correlate related inputs, and an opt imization algorithm, whose objective is to minimize CPU utilization, t ransforms the end-to-end requirements into a set of intermediate rate constraints on the tasks. If the algorithm fails, a restructuring tool attempts to eliminate bottlenecks by transforming the application, wh ich is then resubmitted into the assignment algorithm. The final resul t is a schedulable set of fully periodic tasks, which collaboratively maintain the end-to-end constraints.