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Model-Based Design for Embedded Systems- P16

Model-Based Design for Embedded Systems- P16: This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. | 116 Model-Based Design for Embedded Systems 4.6 Conclusion We have provided a framework that allows the modeling and analysis of a variety of schedulability scenarios. In particular our framework supports multi-processor systems rich task-models with timing uncertainties in arrival and execution times possible dependencies a range of scheduling policies and possible preemption of resources. The support of an approximate analysis of stopwatch automata in Uppaal 4.1 is key to the successful schedulability analysis. Furthermore the uncertainty on the periods used in our framework could be generalized to more general task-arrivals where a separate process determines the arrival of tasks. Such situations can be modeled using the structure of our framework by letting the starting of periods be dictated through channel synchronization with the model controlling arrival times. Even with such liberty the overapproximation is still finite and the termination is guaranteed. The scheduling framework provided in this chapter is structured such that an adaptation can be made to accommodate other scheduling polices and inter-task constraints. The former can be achieved by adding another policy model similarly to the three built-in policies FIFO the FPS and the EDF. The latter is achieved through the use of the function calls new_period dependencies_met and completed. Acknowledgment The authors would like to thank Marius Mikucionis for providing the format for listing Uppaal code. References 1. R. Alur C. Courcoubetis and D. Dill. Model-checking for real-time systems. In Proceedings of the Fifth IEEE Symposium on Logic in Computer Science LICS 90 pp. 414-425 Philadelphia PA 1990. IEEE Computer Society Press 1990. 2. R. Alur and D. Dill. Automata for modeling real-time systems. In Proceedings of the 17 th International Colloquium on Automata Languages and Programming ICALP 90 Warwick University Couentry U.K. 1990. Lecture Notes in Computer Science 443 322-335. Springer 1990. .