The Community for Technology Leaders
RSS Icon
Issue No.09 - September (2008 vol.57)
pp: 1261-1276
Robert I. Davis , University of York, York
Attila Zabos , University of York, York
Alan Burns , University of York, York
Efficient exact schedulability tests are required both for on-line admission of applications to dynamic systems and as an integral part of design tools for complex distributed real-time systems. This paper addresses performance issues with exact Response Time Analysis (RTA) for fixed priority pre-emptive systems. Initial values are introduced that improve the efficiency of the standard RTA algorithm (i) when exact response times are required, and (ii) when only exact schedulability need be determined. The paper also explores modifications to the standard RTA algorithm, including; the use of a response time upper bound to determine when exact analysis is needed, incremental computation aimed at faster convergence, and checking tasks in reverse priority order to identify unschedulable tasksets early. The various initial values and algorithm implementations are compared by means of experiments on a PC recording the number of iterations required, and execution time measurements on a real-time embedded microprocessor. Recommendations are provided for engineers tasked with the problem of implementing exact schedulability tests, as part of on-line acceptance tests and spare capacity allocation algorithms, or as part of off-line system design tools.
Multiprocessing/multiprogramming/multitasking, Scheduling, Real-time systems and embedded systems
Robert I. Davis, Attila Zabos, Alan Burns, "Efficient Exact Schedulability Tests for Fixed Priority Real-Time Systems", IEEE Transactions on Computers, vol.57, no. 9, pp. 1261-1276, September 2008, doi:10.1109/TC.2008.66
[1] M.S. Fineberg and O. Serlin, “Multiprogramming for Hybrid Computation,” Proc. AFIPS Fall Joint Computing Conf., pp. 1-13, 1967.
[2] O. Serlin, “Scheduling of Time Critical Processes,” Proc. AFIPS Spring Computing Conf., pp. 925-932, 1972.
[3] C.L. Liu and J.W. Layland, “Scheduling Algorithms for Multiprogramming in a Hard-Real-Time Environment,” J. ACM, vol. 20, no. 1, pp. 46-61, Jan. 1973.
[4] J.Y.-T. Leung and J. Whitehead, “On the Complexity of Fixed-Priority Scheduling of Periodic Real-Time Tasks,” Performance Evaluation, vol. 2, no. 4, pp. 237-250, Dec. 1982.
[5] M. Joseph and P.K. Pandya, “Finding Response Times in a Real-Time System,” The Computer J., vol. 29, no. 5, pp. 390-395, Oct. 1986.
[6] J.P. Lehoczky, L. Sha, and Y. Ding, “The Rate-Monotonic Scheduling Algorithm: Exact Characterization and Average Case Behavior,” Proc. 10th IEEE Real-Time Systems Symp., pp. 166-172, 1989.
[7] L. Sha, R. Rajkumar, and J.P. Lehoczky, “Priority Inheritance Protocols: An Approach to Real-Time Synchronization,” IEEE Trans. Computers, vol. 39, no. 9, pp. 1175-1185, Sept. 1990.
[8] J.P. Lehoczky, “Fixed Priority Scheduling of Periodic Task Sets with Arbitrary Deadlines,” Proc. 11th IEEE Real-Time Systems Symp., pp. 201-209, Dec. 1990.
[9] T.P. Baker, “Stack-Based Scheduling of Real-Time Processes,” Real-Time Systems J., vol. 3, no. 1, pp. 67-100, 1991.
[10] K.W. Tindell, “Using Offset Information to Analyse Static Priority Pre-Emptively Scheduled Task Sets,” Technical Report YCS-92-182, Dept. of Computer Science, Univ. of York, 1992.
[11] N.C. Audsley, A. Burns, M. Richardson, K.W. Tindell, and A.J. Wellings, “Applying New Scheduling Theory to Static Priority Pre-Emptive Scheduling,” Software Eng. J., vol. 8, no. 5, pp. 284-292, Sept. 1993.
[12] K.W. Tindell, A. Burns, and A.J. Wellings, “An Extendible Approach for Analyzing Fixed Priority Hard Real-Time Tasks,” Real-Time Systems, vol. 6, no. 2, pp. 133-151, Mar. 1994.
[13] M. Sjodin and H. Hansson, “Improved Response Time Analysis Calculations,” Proc. 19th IEEE Real-Time Systems Symp., pp. 399-408, Dec. 1998.
[14] R.J. Bril, W.F.J. Verhaegh, and E-J.D. Pol, “Initial Values for On-line Response Time Calculations,” Proc. 15th Euromicro Conf. Real-Time Systems, pp. 13-22, July 2003.
[15] E. Bini and G.C. Buttazzo, “Measuring the Performance of Schedulability Tests,” Real-Time Systems, vol. 30, nos. 1-2, pp.129-154, May 2005.
[16] W-C. Lu, J-W. Hsieh, W-K. Shih, and T-W. Kuo, “A Faster Exact Schedulability Analysis for Fixed-Priority Scheduling,” J. Systems and Software, vol. 79, no. 12, pp. 1744-1753, Dec. 2006.
[17] W-C. Lu, K-J. Lin, H-W. Wei1, and W-K. Shih, “Period-Dependent Initial Values for Exact Schedulability Test of Rate Monotonic Systems,” Proc. 21st Int'l Parallel and Distributed Processing Symp., pp. 1-8, Mar. 2007.
[18] E. Bini and S.K. Baruah, “Efficient Computation of Response Time Bounds under Fixed-Priority Scheduling,” Proc. 15th Int'l Conf. Real-Time and Network Systems, pp. 95-104, Mar. 2007.
[19] E. Bini and G.C. Buttazzo, “Schedulability Analysis of Periodic Fixed Priority Systems,” IEEE Trans. Computers, vol. 53, no. 11, pp.1462-1473, Nov. 2004.
[20] A. Zuhily and A. Burns, “Optimality of (D-J)-Monotonic Priority Assignment,” Information Processing Letters, no. 103, pp. 247-250, Apr. 2007.
[21] R.J. Bril, J.J. Lukkien, and W.F.J. Verhaegh, “Worst-Case Response Time Analysis of Real-Time Tasks under Fixed-Priority Scheduling with Deferred Preemption Revisited,” Proc. 19th Euromicro Conf. Real-Time Systems, pp. 269-279, July 2007.
[22] N.C. Audsley, “Flexible Scheduling of Hard Real-Time Systems,” PhD thesis, Dept. of Computer Science, Univ. of York, 1993.
[23] http:/, 2007.
[24] “RapiTime White Paper: Worst-Case Execution Time Analysis,”, 2007.
[25] R.I. Davis, A. Burns, R.J. Bril, and J.J. Lukkien, “Controller Area Network (CAN) Schedulability Analysis: Refuted, Revisited and Revised,” Real-Time Systems, vol. 35, no. 3, pp. 239-272, Apr. 2007.
[26] E. Bini, G.C. Buttazzo, and G.M. Buttazzo, “Rate Monotonic Scheduling: The Hyperbolic Bound,” IEEE Trans. Computers, vol. 52, no. 7, pp. 933-942, July 2003.
[27] S. Lauzac, R. Melhem, and D. Mosse, “An Improved Rate-Monotonic Admission Control and Its Applications,” IEEE Trans. Computers, vol. 52, no. 3, pp. 337-350, Mar. 2003.
[28] R.I. Davis, A. Zabos, and A. Burns, “Efficient Exact Schedulability Tests for Fixed Priority Pre-Emptive Systems,” Technical Report YCS-418-2007, Dept. of Computer Science, Univ. of York, 2007.
[29] R.I. Davis and A. Burns, “Robust Priority Assignment for Fixed Priority Real-Time Systems,” Proc. 28th IEEE Real-Time Systems Symp., pp. 1-12, 2007.
16 ms
(Ver 2.0)

Marketing Automation Platform Marketing Automation Tool