Schedulability Analysis of Real-Time Systems with Stochastic Task Execution Times
2006 (English)In: ARTES: A network for Real-Time research and graduate Education in Sweden 1997-2006 / [ed] Hans Hansson, Uppsala: The Department of Information Technology , 2006, 123-159 p.Chapter in book (Other academic)
For soft real-time applications, a system is considered to function correctly even if some timeliness requirements are occasionally broken, since this leads only to a tolerable reduction of the service quality. Analysis of such a system should be focused on the degree to which the system meets its timeliness requirements rather than on a binary answer indicating whether the whole system is schedulable or not. In many soft real-time applications, the task execution times vary also widely since they are dependent on many parameters. In such a context, analysis techniques based on worst case execution time assumption will lead to very pessimistic results, and many techniques have been developed to consider a more realistic model that assumes tasks to have varying execution times with given probability distributions. The chapter presents one of such techniques. It describes an analytic method to produce the expected deadline miss ratio of the tasks and the task graphs that represent a software real-time application. The reported method improves the currently existing ones by providing exact solutions for larger and less restricted task sets. In particular, it allows continuous task execution time probability distributions, and supports different scheduling policy. Furthermore, task dependencies and arbitrary deadlines are supported by the proposed technique.
Place, publisher, year, edition, pages
Uppsala: The Department of Information Technology , 2006. 123-159 p.
, Technical report / Department of Information Technology, Uppsala University, ISSN 1404-3203 ; 2006:006
embedded systems, soft real-time, schedulability analysis, stochastic task execution, analytic method
IdentifiersURN: urn:nbn:se:liu:diva-33838Local ID: MDH-MRTC-197/2006-1-SEISBN: 91-506-1859-8Archive number: 19909OAI: oai:DiVA.org:liu-33838DiVA: diva2:254661
MRTC report, ISSN 1404-3041 No, 197/20062009-10-092009-10-092016-06-30Bibliographically approved