Journal of the Institute of Electronics Engineers of Korea CI (전자공학회논문지CI)

The Institute of Electronics and Information Engineers (대한전자공학회)
권호 표지

A Soft Aperiodic Real-Time Task Scheduling Algorithm Supporting Maximum Slack Time

최대여유시간 제공 연성 비주기 실시간 태스크 스케줄링 알고리즘

  • 임덕주 ((주) 케이디이컴 소프트웨어 개발실) ;
  • 박성한 (한양대학교 컴퓨터공학부)
  • Published : 2000.07.01
Download PDF
⟨ Previous Next ⟩

Abstract

The purpose of this paper is to minimize the a slack computation time of the scheduling of a soft aperiodic real-time tasks in a fixed priority real-time system. The proposed algorithm reduces the computation overhead at on-line time and supports the maximum slack time assigned for aperiodic real-time tasks. The proposed algorithm has 10~20% more response time for aperiodic real-time tasks than that of Slack Stealing Algorithm that offers optimal response time in fixed priority real-time system. However, the performance of the proposed algorithm is seven times better in a scheduling overhead.

본 논문은 고정 우선순위 실시간 시스템에서 연성 비주기 실시간 태스크의 on-line 응답시간을 줄이기 위한 연산의 최소화에 목적이 있다. 제안하는 알고리즘은 온라인 시의 오버헤드를 줄이면서, 동시에 비주기 태스크에 할당할 수 있는 최대의 여유시간을 제공함으로써 목표를 만족시킨다. 제안하는 알고리즘은 고정우선 순위 비주기 실시간 태스크 스케줄링에서 off-line시 최적의 응답시간을 내는 알고리즘인 Slack Stealing에 비해 응답시간의 손실이 거의 없으면서 오버헤드 측면에서 7배 가량의 좋은 성능을 나타낸다.

Keywords

References

  1. E. Douglas Jensen, 'Scheduling in Real-Time Systems,' http://www.realtime- os.com/sched o3.html. November 20, 1996
  2. C. L. Liu and J. W. Layland. 'Scheduling algorithms for multiprogramming in a hard real-time environment.' Journal of the ACM. Vo1.20, pp. 46-61, Jan. 1973 https://doi.org/10.1145/321738.321743
  3. B. Sprunt, L. Sha, and J. P. Lehoczky, 'Aperiodic task scheduling for hard real-time systems,' The Journal of Real-Time Systems, vol. 1, pp. 27-69, Dec. 1989 https://doi.org/10.1007/BF02341920
  4. J. P. Lehoczky, L.Sha, and J.K. Strosnider, 'Enhanced aperiodic responsiveness in hard real-time environment,' in Proceedings of the Real-Time Systems Symposium, pp. 261-270, Dec. 1987
  5. C.M. Krishna, Kang G. Shin, 'Real-Time Systems', McGRAW-HILL, pp.47-80, 1977
  6. J.P. Lehoczky and S.Ramos-Thuel. 'An optimal algorithm for scheduling soft-aperiodic tasks in fixed-priority preemptive systems.' in Proceedings of the IEEE Real-Time Systems Symposium, pp. 110-123, Dec. 1992 https://doi.org/10.1109/REAL.1992.242671
  7. R. I. Davis, K. W. Tindell, and A. Burns, 'Scheduling slack time in fixed-priority preemptive systems,' in Proceedings of the Real-Time Systems Symposium, pp. 160- 171, Dec. 1993 https://doi.org/10.1109/REAL.1993.393496
  8. 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, 1982
  9. J.P.Lehoczky, L.Sha, J.K.Strosnider, and H.Tokuda, 'Fixed priority-scheduling theory for hard real-time systems,' A.M. van Tilborg and G. M. Koob, eds., Foundations of Real-Time Computing: Scheduling and Resource Management, Kluwer Academic Publishers, Boston, pp. 1-30, 1991
  10. L. Sha, R. Rajkumar, and J. P. Lehoczky, 'Priority inheritance protocols: An approach to real-time synchronization,' IEEE Transactions on Computers, Vol.39, No.9, pp.1175-1185, 1990 https://doi.org/10.1109/12.57058
  11. J. P. Lehoczky, 'Fixed priority scheduling of periodic task sets with arbitrary deadlines,' Proceedings of the Real-Time Systems Symposium, pp. 201-209, Dec. 1990 https://doi.org/10.1109/REAL.1990.128748
  12. Giorgio C. Buttazzo, Scuola Superiore S. Anna, 'Hard Real-Time Computing Systems-Predictable Scheduling Algorithms and Applications', Kluwer Academic Publisher, 1997