Guaranteeing real-time requirements with resource-based calibration of periodic processes

The paper presents a comprehensive design methodology for guaranteeing end to end requirements of real time systems. Applications are structured as a set of process components connected by asynchronous channels, in which the end points are the system´s external inputs and outputs. Timing constraints are then postulated between these inputs and outputs; they express properties such as end to end propagation delay, temporal input sampling correlation, and allowable separation times between updated output values. The automated design method works as follows: First new tasks are created to correlate related inputs, and an optimization algorithm, whose objective is to minimize CPU utilization, transforms 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, which is then resubmitted into the assignment algorithm. The final result is a schedulable set of fully periodic tasks, which collaboratively maintain the end to end constraints