Online Slack-Stealing Scheduling with Modified laEDF in Real-Time Systems
Abstract
:1. Introduction
2. System Design
- denotes the WCET of a periodic task . (i.e., the WCET needed by the processor to execute an instance of the task without interruption)
- denotes the WCET of an aperiodic task job .
- denotes the remaining computation time of the current instance of task .
- denotes the absolute deadline assigned to a periodic task .
- denotes the absolute deadline assigned to an aperiodic task job by the algorithm.
- denotes the arrival time of a periodic task .
- denotes the arrival time of an aperiodic task job . (i.e., the time at which the job is activated and becomes ready to execute)
- denotes slack until the earliest periodic task deadline.
- denotes the response time of the i-th aperiodic task job.
3. The Slack-Stealing with Modified laEDF Algorithm
3.1. Look-Ahead EDF
Algorithm 1 Look-ahead EDF(laEDF) algorithms. |
|
3.2. The SSML Algorithm
Algorithm 2 SSML algorithms. |
|
3.3. Illustrative Example
4. Evaluation
- SSML: slack-stealing method with modified laEDF as a slack computation method.
- Original TBS: a scheduling method for assigning the deadline for each aperiodic job by using its WCET
- ATBS: adaptive TBS with the deadline of each aperiodic job by using predicted execution time.
- ATBS+VRA: ATBS with VRA for improving the average response time of aperiodic tasks.
- ORACLE: a scheduling method for assigning the deadlines of aperiodic tasks, where OS can know the exact job amounts.
- ORACLE+VRA: ORACLE with VRA for improving the average response time of aperiodic tasks.
5. Conclusions
Author Contributions
Funding
Conflicts of Interest
Abbreviations
TBS | Total bandwidth server |
WCET | Worst-case execution time |
ATBS | Adaptive TBS |
EDF | Earliest deadline first |
DVS | Dynamic voltage scaling |
CBS | Constant bandwidth server |
VRA | Virtual release advancing |
ANRT | Average normalized response time |
AET | Actual execution time |
References
- Kato, S.; Yamasaki, N. Scheduling aperiodic tasks using total bandwidth server on multiprocessors. In Proceedings of the 2008 IEEE/IFIP International Conference on Embedded and Ubiquitous Computing, Shanghai, China, 17–20 December 2008; Volume 1, pp. 82–89. [Google Scholar] [CrossRef]
- Spuri, B. Efficient aperiodic service under earliest deadline scheduling. In Proceedings of the 1994 Proceedings Real-Time Systems Symposium, San Juan, PR, USA, 7–9 December 1994; pp. 2–11. [Google Scholar] [CrossRef]
- Strosnider, J.K.; Lehoczky, J.P.; Sha, L. The deferrable server algorithm for enhanced aperiodic responsiveness in hard real-time environments. IEEE Trans. Comput. 1995, 44, 73–91. [Google Scholar] [CrossRef] [Green Version]
- Sprunt, B.; Sha, L.; Lehoczky, J. Aperiodic task scheduling for Hard-Real-Time systems. Real Time Syst. 1989, 1, 27–60. [Google Scholar] [CrossRef]
- Liu, C.L.; Layland, J.W. Scheduling algorithms for multiprogramming in a hard-real-time environment. J. ACM 1973, 20, 46–61. [Google Scholar] [CrossRef]
- Abeni, L.; Buttazzo, G. Integrating multimedia applications in hard real-time systems. In Proceedings of the 19th IEEE Real-Time Systems Symposium (Cat. No. 98CB36279), Madrid, Spain, 2–4 December 1998; pp. 4–13. [Google Scholar] [CrossRef]
- Peng, A.; Guo, R.; Wu, H.; Deng, C.; Zheng, L. Adaptive real-time scheduling for mixed task sets based on total bandwidth server. In Proceedings of the 2017 10th International Conference on Intelligent Computation Technology and Automation (ICICTA), Changsha, China, 9–10 October 2017; pp. 11–15. [Google Scholar] [CrossRef]
- Tanaka, K. Adaptive Total Bandwidth Server: Using Predictive Execution Time. In Embedded Systems: Design, Analysis and Verification; Schirner, G., Götz, M., Rettberg, A., Zanella, M.C., Rammig, F.J., Eds.; Springer: Berlin/Heidelberg, Germany, 2013; pp. 250–261. [Google Scholar] [Green Version]
- Duy, D.; Tanaka, K. An effective approach for improving responsiveness of Total Bandwidth Server. In Proceedings of the 2017 8th International Conference of Information and Communication Technology for Embedded Systems (IC-ICTES), Chonburi, Thailand, 7–9 May 2017; pp. 1–6. [Google Scholar] [CrossRef]
- Lehoczky, J.P.; Ramos-Thuel, S. An optimal algorithm for scheduling soft-aperiodic tasks in fixed-priority preemptive systems. In Proceedings of the Real-Time Systems Symposium, Phoenix, AZ, USA, 2–4 December 1992; pp. 110–123. [Google Scholar] [CrossRef]
- Davis, R.I.; Tindell, K.W.; Burns, A. Scheduling slack time in fixed priority pre-emptive systems. In Proceedings of the 1993 Proceedings Real-Time Systems Symposium, Raleigh Durham, NC, USA, 1–3 December 1993; pp. 222–231. [Google Scholar] [CrossRef]
- Tia, T.S.; Liu, J.W.S.; Shankar, M. Algorithms and optimality of scheduling soft aperiodic requests in fixed-priority preemptive systems. Real Time Syst. 1996, 10, 23–43. [Google Scholar] [CrossRef] [Green Version]
- Pillai, P.; Shin, K.G. Real-time dynamic voltage scaling for low-power embedded operating Systems. SIGOPS Oper. Syst. Rev. 2001, 35, 89–102. [Google Scholar] [CrossRef]
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Share and Cite
Jeon, W.; Kim, W.; Lee, H.; Lee, C.-H. Online Slack-Stealing Scheduling with Modified laEDF in Real-Time Systems. Electronics 2019, 8, 1286. https://doi.org/10.3390/electronics8111286
Jeon W, Kim W, Lee H, Lee C-H. Online Slack-Stealing Scheduling with Modified laEDF in Real-Time Systems. Electronics. 2019; 8(11):1286. https://doi.org/10.3390/electronics8111286
Chicago/Turabian StyleJeon, Wonbo, Wonsop Kim, Heoncheol Lee, and Cheol-Hoon Lee. 2019. "Online Slack-Stealing Scheduling with Modified laEDF in Real-Time Systems" Electronics 8, no. 11: 1286. https://doi.org/10.3390/electronics8111286
APA StyleJeon, W., Kim, W., Lee, H., & Lee, C.-H. (2019). Online Slack-Stealing Scheduling with Modified laEDF in Real-Time Systems. Electronics, 8(11), 1286. https://doi.org/10.3390/electronics8111286