Current Results on EDZL Scheduling for Multiprocessor Real-Time Systems

Many optimal uniprocessor schedulers, such as earliest deadline first (EDF) and rate monotonic (RM), do not have a good schedulability bound on multiprocessor systems. In this paper, we study an on-line algorithm earliest deadline first until Zero laxity (EDZL) for multiprocessor systems. A set of tasks scheduled by EDZL is scheduled using EDF until a job experiences a zero laxity. To avoid the job from missing its deadline, the priority of the job is immediately promoted to the highest priority. We derive the schedulability bound of 3/2+\umax-1/2\ for two-processor systems, where umax is the maximum utilization of an individual task in the given task set. We also discuss the best known upper bound and lower bound on EDZL schedulability conditions.

[1]  Theodore P. Baker,et al.  An analysis of EDF schedulability on a multiprocessor , 2005, IEEE Transactions on Parallel and Distributed Systems.

[2]  Suk Kyoon Lee.  On-line multiprocessor scheduling algorithms for real-time tasks , 1994, Proceedings of TENCON'94 - 1994 IEEE Region 10's 9th Annual International Conference on: 'Frontiers of Computer Technology'.

[3]  Aloysius K. Mok,et al.  Multiprocessor On-Line Scheduling of Hard-Real-Time Tasks , 1989, IEEE Trans. Software Eng..

[4]  Sanjoy K. Baruah,et al.  Deadline-based scheduling of periodic task systems on multiprocessors , 2002, Inf. Process. Lett..

[5]  Sang Hyuk Son,et al.  New Strategies for Assigning Real-Time Tasks to Multiprocessor Systems , 1995, IEEE Trans. Computers.

[6]  Shun-Shii Lin,et al.  Schedulability issues for EDZL scheduling on real-time multiprocessor systems , 2008, Inf. Process. Lett..

[7]  Daniel F. Garcia,et al.  Utilization Bounds for EDF Scheduling on Real-Time Multiprocessor Systems , 2004, Real-Time Systems.

[8]  Jane W.-S. Liu,et al.  Validating timing constraints in multiprocessor and distributed real-time systems , 1994, 14th International Conference on Distributed Computing Systems.

[9]  Yookun Cho,et al.  Predictability of earliest deadline zero laxity algorithm for multiprocessor real-time systems , 2006, Ninth IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC'06).

[10]  Sanjoy K. Baruah,et al.  Priority-Driven Scheduling of Periodic Task Systems on Multiprocessors , 2003, Real-Time Systems.