Browse > Article

Integrating Deadline with Laxity for Real-time Scheduling in Multiprocessor Systems  

조성제 (단국대학교 정보컴퓨터학부 컴퓨터과학전공)
Abstract
For real-time systems, multiprocessor support is indispensable to handle the large number of requests. Existing real-time on-line scheduling algorithms such as Earliest Deadline First Algorithm (EDF) and Least Laxity Algorithm (LLA) may not be suitable for scheduling real-time tasks in multiprocessor systems. Although EDF has low context switching overhead, it suffers from "multiple processor anomalies." LLA has been shown as suboptimal, but has the potential for higher context switching overhead. Earliest Deadline Zero Laxity (EDZL) solved somewhat the problems of those algorithms, however is suboptimal for only two processors. Another algorithm EDA2 shows very good performance in overload phase, however, is not suboptimal for muitiprocessors. We propose two on-line scheduling algorithms, Earliest Deadline/Least Laxity (ED/LL) and ED2/LL. ED/LL is suboptimal for multiprocessors, and has low context switching overhead and low deadline miss rate in normal load phase. However, ED/LL is ineffective when the system is overloaded. To solve this problem, ED2/LL uses ED/LL or EDZL in normal load phase and uses EDA2 in overload phase. Experimental results show that ED2/LL achieves good performance in overload phase as wet] as in normal load phase.oad phase.
Keywords
ED/LL (Earliest Deadline / Least Laxity); ED2/LL;
Citations & Related Records
연도 인용수 순위
  • Reference
1 M. L. Dertouzos and A. K. Mok, 'Multiprocessor on-line scheduling of hard-real-time tasks', IEEE Trans. on Software Engineering, vol.15, no.12, pp.1497-1506, Dec. 1989   DOI   ScienceOn
2 I. Ripoll, A. Crespo, and A. Garcia-Fornes, 'An optimal algorithm for scheduling soft aperiodic tasks in dynamic-priority preemptive systems', IEEE Trans. on Software Engineering, vol.23, no.6, pp.388-400, Jun. 1997   DOI   ScienceOn
3 H. Chetto and M. Chetto, 'Some results of the earliest deadline scheduling algorithm', IEEE Trans. Software Engineering, vol.15, no.10, pp.1261-1269, Oct. 1989   DOI   ScienceOn
4 S. Baruah, J. Gehrke and C. G. Plaxton, 'Fast scheduling of periodic tasks on mulitiple resources', Proc. 9th International Parallel Processing Symp., pp.280-288, 1995   DOI
5 J. Y.-T. Leung, 'A new algorithm for scheduling periodic, real-time tasks', Algorithmica, vol.4, pp.209-219, 1989   DOI
6 R. Clark, 'Scheduling dependent real-time activities', PhD thesis, Computer Science Department, CarnegieMellon University, 1990
7 S. Baruah, G. Koren, B. Mishra, A. Raghunathan, L. Rosier, and D. Shasha, 'On-line scheduling in the presence of overload', 1991 IEEE Symposium on Foundations of Computer Science, pp.100-110, Oct. 1991   DOI
8 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. of 12th Real-Time Systems Symp., pp.106-115, Dec. 1991   DOI
9 C. D. Locke, 'Best-effort decision making for real-time scheduling', PhD thesis, Computer Science Department, Carnegie-Mellon University, 1996
10 C. Liu and J. Layland, 'Scheduling algorithms for multiprogramming in a hard real-time environment', Journal of the ACM, vol.20, no.1, pp.46-61, 1973   DOI
11 A. Srinivasan and S. Baruah. 'Deadline-based Scheduling of Periodic Task Systems on Multiprocessors', Information Processing Letters, Accepted for ublication   DOI   ScienceOn
12 S. K. Lee and D. Epley, 'On-line scheduling algorithms of real-time sporadic tasks in multiprocessor systems', Technical Report 92-3, Computer Science, University of Iowa,, 1992
13 S. Cho, S. K. Lee and H. Yoo, 'On-line scheduling algorithms for hard real-time sporadic tasks', Journal of KISS(A), vol.25, no.7, pp.708-718, July 1998
14 S. K. Lee, 'On-line multiprocessor scheduling algorithms for real-time tasks'. Proc. IEEE Region 10's Ninth Annual International Conf., pp.607-611, Aug. 1994   DOI
15 K. Jeffay, 'Scheduling sporadic tasks with shared resources in hard-real-time systems', Proc. of 13th IEEE Real-time Systems Symp., pp.89-99, Dec. 1992
16 S. Baruah, 'Fairness in periodic real-time scheduling', Proc. of 16th IEEE Real-time Systems Symp., pp.200-209, Dec. 1995
17 S. Baruah, N. Cohen, C. G. Plaxton, and D. Varvel, 'Proportionate progress: a notion of fairness in resource allocation', Algorithmica, vol.15, pp.600-625, 1996   DOI