Adding Robustness in Dynamic Preemptive Scheduling

In this paper we introduce a robust earliest deadline scheduling algorithm for dealing with hard aperiodic tasks under overloads in a dynamic real-time environment. The algorithm synergistically combines many features including dynamic guarantees, graceful degradation in overloads, deadline tolerance, resource reclaiming, and dynamic re-guarantees. A necessary and sufficient schedulability test is presented, and an efficient 0(n) guarantee algorithm is proposed. The new algorithm is evaluated via simulation and compared to several baseline algorithms. The experimental results show excellent performance of the new algorithm in normal and overload conditions.

[1]  Jacek Blazewicz,et al.  Scheduling Dependent Tasks with Different Arrival Times to Meet Deadlines , 1976, Performance.

[2]  Hideyuki Tokuda,et al.  Implementation of a Time-Driven Scheduler for ReaI-Time Operating Systems , 1987, RTSS.

[3]  G. C. Buttazzo,et al.  RE: Robust Earliest Deadline Scheduling , 1993 .

[4]  Krithi Ramamritham,et al.  Resource Reclaiming in Real-Time , 1990, RTSS.

[5]  Hongyi Zhou,et al.  Dynamic Scheduling of Hard Real-Time Tasks and Real-Time Threads , 1992, IEEE Trans. Software Eng..

[6]  Michael L. Dertouzos,et al.  Control Robotics: The Procedural Control of Physical Processes , 1974, IFIP Congress.

[7]  Miron Livny,et al.  Earliest deadline scheduling for real-time database systems , 1991, [1991] Proceedings Twelfth Real-Time Systems Symposium.

[8]  Lui Sha,et al.  Solutions for Some Practical Problems in Prioritized Preemptive Scheduling , 1986, RTSS.

[9]  C. D. Locke,et al.  Best-effort decision-making for real-time scheduling , 1986 .

[10]  James W. Layland,et al.  Scheduling Algorithms for Multiprogramming in a Hard-Real-Time Environment , 1989, JACM.

[11]  Krithi Ramamritham,et al.  The integration of deadline and criticalness in hard real-time scheduling , 1988, Proceedings. Real-Time Systems Symposium.

[12]  Charles U. Martel,et al.  On non-preemptive scheduling of period and sporadic tasks , 1991, [1991] Proceedings Twelfth Real-Time Systems Symposium.

[13]  Kishor S. Trivedi,et al.  Transient overloads in fault-tolerant real-time systems , 1989, [1989] Proceedings. Real-Time Systems Symposium.

[14]  Krithi Ramamritham,et al.  Dynamic Task Scheduling in Hard Real-Time Distributed systems , 1984, IEEE Software.

[15]  Aloysius Ka-Lau Mok,et al.  Fundamental design problems of distributed systems for the hard-real-time environment , 1983 .