This Article 
   
 Share 
   
 Bibliographic References 
   
 Add to: 
 
Digg
Furl
Spurl
Blink
Simpy
Google
Del.icio.us
Y!MyWeb
 
 Search 
   
Scheduling for Overload in Real-Time Systems
September 1997 (vol. 46 no. 9)
pp. 1034-1039

Abstract—No on-line scheduling algorithm operating in an uniprocessor environment can guarantee to obtain a useful processor utilization greater than 0.25 under conditions of overload. This result holds in the general case, where the deadlines of the input tasks can be arbitrarily "tight." We address here the issue of improving overload performance in environments where there is a limit on the tightness of task deadlines. In particular, we present a new scheduling algorithm, ROBUST, that efficiently takes advantage of these limits to provide improved overload performance and is asymptotically optimal. We also introduce the concept of overload tolerance, wherein a system's overload performance never falls below its design capacity, and describe how ROBUST may be used to construct overload tolerant systems.

[1] S. Baruah and J. Haritsa, "ROBUST: A Hardware Solution to Real-Time Overload," Proc. 13th ACM SIGMETRICS Conf., pp. 207-216,Santa Clara, Calif., May 1993.
[2] S.K. Baruah, J. Haritsa, and N. Sharma, “On-Line Scheduling to Maximize Task Completions,” Proc. IEEE Real-Time Systems Symp., pp. 228-236, Dec. 1994.
[3] S. Baruah, G. Koren, D. Mao, B. Mishra, A. Raghunathan, L. Rosier, D. Shasha, and F. Wang, "On the Competitiveness of On-Line Real-Time Task Scheduling," Proc. 12th Real-Time Systems Symp.,San Antonio, Tex., Dec. 1991.
[4] S. Baruah, G. Koren, B. Mishra, A. Raghunathan, L. Rosier, and D. Shasha, "On-Line Scheduling in the Presence of Overload," Proc. 32nd Ann. IEEE Symp. Foundations of Computer Science,San Juan, Puerto Rico, Oct. 1991.
[5] S. Biyabani, J. Stankovic, and K. Ramamritham, "The Integration of Deadline and Criticalness in Hard Real-Time Scheduling," Proc. Ninth Real-Time Systems Symp., Dec. 1988.
[6] S. Cheng, J. Stankovic, and K. Ramamritham, "Scheduling Survey," Hard Real-Time Systems Tutorial, Dec. 1988.
[7] M. Dertouzos, "Control Robotics: The Procedural Control of Physical Processors," Proc. IFIP Congress, pp. 807-813, 1974.
[8] J. Dey, J. Kurose, D. Towsley, C. Krishna, and M. Girkar, "Efficient On-Line Processor Scheduling for a Class of IRIS Real-Time Tasks," Proc. 13th ACM SIGMETRICS Conf., pp. 217-228,Santa Clara, Calif., May 1993.
[9] M.R. Garey and D.S. Johnson, Computers and Intractability: A Guide to the Theory of NP-Completeness.New York: W.H. Freeman, 1979.
[10] J. Haritsa, M. Livny, and M. Carey, “On Being Optimistic about Real-Time Constraints,” Proc. Ninth ACM Symp. Principles of Database Systems, 1990.
[11] J. Haritsa, M. Livny, and M. Carey, “Earliest Deadline Scheduling for Real-Time Database Systems,” Proc. 12th Real-Time Systems Symp., Dec. 1991.
[12] E. Jensen, M. Carey, and M. Livny, "A Time-Driven Scheduling Model for Real-Time Operating Systems," Proc. IEEE Real-Time Systems Symp., Dec. 1985.
[13] G. Koren and D. Shasha, “D-Over: An Optimal On-Line Scheduling Algorithm for Overloaded Real-Time Systems,” Proc. IEEE Real-Time Systems Symp., pp. 290-299, Dec. 1992.
[14] C.L. Liu and J.W. Layland, “Scheduling Algorithms for Multiprogramming in a Hard Real-Time Environment,” J. ACM, vol. 20, no. 1, pp. 40-61, 1973.
[15] C. D. Locke, "Best-Effort Decision Making for Real-Time Scheduling," PhD thesis, Computer Science Dept., Carnegie Mellon Univ., 1986.
[16] A. Mok, "Fundamental Design Problems of Distributed Systems for the Hard Real-Time Environment," PhD thesis, Laboratory for Computer Science, Massachusetts Inst. of Tech nology, May 1983.
[17] J.A. Stankovic, M. Spuri, M. Di Natale, and G. Buttazzo, “Implications of Classical Scheduling Results for Real-Time Systems,” IEEE Computer, vol. 28, no. 6, June 1995.

Index Terms:
Real-time systems, uniprocessor scheduling, overload tolerance, performance evaluation, processor utilization.
Citation:
Sanjoy K. Baruah, Jayant R. Haritsa, "Scheduling for Overload in Real-Time Systems," IEEE Transactions on Computers, vol. 46, no. 9, pp. 1034-1039, Sept. 1997, doi:10.1109/12.620484
Usage of this product signifies your acceptance of the Terms of Use.