Timing Faults and Mixed Criticality Systems

  • Alan Burns
  • Sanjoy Baruah
Part of the Lecture Notes in Computer Science book series (LNCS, volume 6875)


Many safety-critical embedded systems are subject to certification requirements. However, only a subset of the functionality of the system may be safety-critical and hence subject to certification; the rest of the functionality is non safety-critical and does not need to be certified, or is certified to a lower level. The resulting mixed criticality system offers challenges both for static analysis and run-time monitoring. This paper is concerned with timing failures and how they can arise and be tolerated. The main causes of these errors are faults in the estimation of worst-case execution times (WCETs). For different levels of criticality, different forms of static analysis for WCET are employed. This give rise to a novel implementation scheme for the fixed priority uniprocessor scheduling of mixed criticality systems. The scheme requires that jobs have their execution times monitored (as is usually the case in high integrity systems). This results in higher levels of schedulability than previously published.


Task System Priority Assignment Sporadic Task Relative Deadline Sporadic Task System 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. 1.
    de Niz, D., Lakshmanan, K., Rajkumar, R.: On the scheduling of mixed-criticality real-time task sets. In: Proceedings of the IEEE Real-Time Systems Symposium, pp. 291–300 (2009)Google Scholar
  2. 2.
    Vestal, S.: Preemptive scheduling of multi-criticality systems with varying degrees of execution time assurance. In: Proceedings of the IEEE Real-Time Systems Symposium, Tucson, AZ, pp. 239–243. IEEE Computer Society Press, Los Alamitos (2007)Google Scholar
  3. 3.
    Baruah, S., Vestal, S.: Schedulability analysis of sporadic tasks with multiple criticality specifications. In: ECRTS, pp. 147–155 (2008)Google Scholar
  4. 4.
    Baruah, S., Li, H., Stougie, L.: Towards the design of certifiable mixed-criticality systems. In: Proceedings of the IEEE Real-Time Technology and Applications Symposium (RTAS). IEEE, Los Alamitos (2010)Google Scholar
  5. 5.
    Baruah, S., Bonifaci, V., D’Angelo, G., Li, H., Marchetti-Spaccamela, A., Megow, N., Stougie, L.: Scheduling real-time mixed-criticality jobs. In: Hliněný, P., Kučera, A. (eds.) MFCS 2010. LNCS, vol. 6281, pp. 90–101. Springer, Heidelberg (2010)CrossRefGoogle Scholar
  6. 6.
    Mok, A.K.: Fundamental Design Problems of Distributed Systems for The Hard-Real-Time Environment. PhD thesis, Laboratory for Computer Science, Massachusetts Institute of Technology (1983), available as Technical Report No. MIT/LCS/TR-297Google Scholar
  7. 7.
    Baruah, S., Mok, A., Rosier, L.: Preemptively scheduling hard-real-time sporadic tasks on one processor. In: Proceedings of the 11th Real-Time Systems Symposium, Orlando, Florida, pp. 182–190. IEEE Computer Society Press, Los Alamitos (1990)Google Scholar
  8. 8.
    Audsley, N.: On priority assignment in fixed priority scheduling. Information Processing Letters 79, 39–44 (2001)CrossRefzbMATHGoogle Scholar
  9. 9.
    Li, H., Baruah, S.: An algorithm for scheduling certifiable mixed-criticality sporadic task systems. In: Proceedings of the Real-Time Systems Symposium, San Diego, CA, pp. 183–192. IEEE Computer Society Press, Los Alamitos (2010)Google Scholar
  10. 10.
    Baruah, S., Burns, A.: Implementing mixed criticality systems in ada. In: Romanovsky, A., Vardanega, T. (eds.) Ada-Europe 2011. LNCS, vol. 6652, pp. 174–188. Springer, Heidelberg (2011)CrossRefGoogle Scholar
  11. 11.
    Leung, J., Whitehead, J.: On the complexity of fixed-priority scheduling of periodic, real-time tasks. Performance Evaluation 2, 237–250 (1982)MathSciNetCrossRefzbMATHGoogle Scholar
  12. 12.
    Burns, A., Littlewood, B.: Reasoning about the reliability of multi-version, diverse real-time systems. In: Proceedings of IEEE Real-Time Systems Symposium (RTSS), pp. 73–81. IEEE Computer Society, Los Alamitos (2010)Google Scholar
  13. 13.
    Abeni, L., Buttazzo, G.: Integrating multimedia applications in hard real-time systems. In: Proceedings of the Real-Time Systems Symposium, Madrid, Spain, pp. 3–13. IEEE Computer Society, Los Alamitos (1998)Google Scholar
  14. 14.
    Bernat, G., Burns, A.: New results on fixed priority aperiodic servers. In: Proceedings 20th IEEE Real-Time Systems Symposium, pp. 68–78 (1999)Google Scholar
  15. 15.
    Caccamo, M., Sha, L.: Aperiodic servers with resource constraints. In: Proceedings of the IEEE Real-Time Systems Symposium (2001)Google Scholar
  16. 16.
    Bernat, G., Burns, A.: Multiple servers and capacity sharing for implementing flexible scheduling. Real-Time Systems Journal 22, 49–75 (2002)CrossRefzbMATHGoogle Scholar
  17. 17.
    Zabos, A., Davis, R., Burns, A., Harbour, M.G.: Spare capacity distribution using exact response-time analysis. In: 17th International Conference on Real-Time and Network Systems, pp. 97–106 (2009)Google Scholar
  18. 18.
    Audsley, N., Burns, A., Richardson, M., Tindell, K., Wellings, A.: Applying new scheduling theory to static priority preemptive scheduling. Software Engineering Journal 8, 284–292 (1993)CrossRefGoogle Scholar
  19. 19.
    Joseph, M., Pandya, P.: Finding response times in a real-time system. BCS Computer Journal 29, 390–395 (1986)MathSciNetCrossRefGoogle Scholar
  20. 20.
    Baruah, S.: Efficient computation of response time bounds for preemptive uniprocessor deadline monotonic scheduling. Technical report (2010),
  21. 21.
    Davis, R., Rothvoss, T., Baruah, S., Burns, A.: Exact quantification of the sub-optimality of uniprocessor fixed priority pre-emptive scheduling. Journal of Real Time Systems 43, 211–258 (2009)CrossRefzbMATHGoogle Scholar
  22. 22.
    Barhorst, J., Belote, T., Binns, P., Hoffman, J., Paunicka, J., Sarathy, P., Scoredos, J., Stanfill, P., Stuart, D., Urzi, R.: White paper: A research agenda for mixed-criticality systems (2009),

Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Alan Burns
    • 1
  • Sanjoy Baruah
    • 2
  1. 1.The University of YorkUK
  2. 2.The University of North CarolinaUSA

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