On the Soft Real-Time Optimality of Global EDF on Uniform Multiprocessors

It has long been known that the global earliest-deadlinefirst (GEDF) scheduler is soft real-time (SRT) optimal for sporadic task systems executing on identical multiprocessor platforms, regardless of whether task execution is preemptive or non-preemptive. This notion of optimality requires deadline tardiness to be provably bounded for any feasible task system. In recent years, there has been interest in extending these SRT optimality results to apply to uniform heterogeneous platforms, in which processors may have different speeds. However, it was recently shown that nonpreemptive GEDF is not SRT optimal on such platforms. The remaining case, preemptive GEDF, has turned out to be quite difficult to tackle and has remained open for a number of years. In this paper, this case is resolved by showing that preemptive GEDF is indeed SRT optimal on uniform platforms, provided a certain job migration policy is used.

[1]  James H. Anderson,et al.  Soft real-time scheduling on multiprocessors , 2006 .

[2]  Michael Pinedo,et al.  Scheduling: Theory, Algorithms, and Systems , 1994 .

[3]  James H. Anderson,et al.  An Optimal Semi-partitioned Scheduler for Uniform Heterogeneous Multiprocessors , 2015, 2015 27th Euromicro Conference on Real-Time Systems.

[4]  Sudarshan K. Dhall,et al.  On a Real-Time Scheduling Problem , 1978, Oper. Res..

[5]  Hennadiy Leontyev,et al.  Generalized tardiness bounds for global multiprocessor scheduling , 2007, Real Time Syst..

[6]  Hennadiy Leontyev,et al.  A Hierarchical Multiprocessor Bandwidth Reservation Scheme with Timing Guarantees , 2008, ECRTS.

[7]  Cong Liu,et al.  Supporting Soft Real-Time Sporadic Task Systems on Heterogeneous Multiprocessors with No Utilization Loss , 2014, ArXiv.

[8]  James H. Anderson,et al.  Tardiness bounds under global EDF scheduling on a multiprocessor , 2005, 26th IEEE International Real-Time Systems Symposium (RTSS'05).

[9]  James H. Anderson,et al.  Scheduling and locking in multiprocessor real-time operating systems , 2011 .

[10]  Hennadiy Leontyev,et al.  A hierarchical multiprocessor bandwidth reservation scheme with timing guarantees , 2008, 2008 Euromicro Conference on Real-Time Systems.

[11]  Hennadiy Leontyev,et al.  Tardiness Bounds for FIFO Scheduling on Multiprocessors , 2007, 19th Euromicro Conference on Real-Time Systems (ECRTS'07).

[12]  James H. Anderson,et al.  On the Soft Real-Time Optimality of Global EDF on Multiprocessors: From Identical to Uniform Heterogeneous , 2015, 2015 IEEE 21st International Conference on Embedded and Real-Time Computing Systems and Applications.

[13]  Sanjoy K. Baruah,et al.  On-line scheduling on uniform multiprocessors , 2001, Proceedings 22nd IEEE Real-Time Systems Symposium (RTSS 2001) (Cat. No.01PR1420).

[14]  James H. Anderson,et al.  Optimal GEDF-based schedulers that allow intra-task parallelism on heterogeneous multiprocessors , 2014, 2014 IEEE 12th Symposium on Embedded Systems for Real-time Multimedia (ESTIMedia).

[15]  Sanjoy Baruah,et al.  Edf scheduling on heterogeneous multiprocessors , 2004 .

[16]  Shui Lam,et al.  A Level Algorithm for Preemptive Scheduling , 1977, J. ACM.

[17]  Shih-Ying Chen,et al.  Optimal Dynamic-Priority Real-Time Scheduling Algorithms for Uniform Multiprocessors , 2008, 2008 Real-Time Systems Symposium.

[18]  Liliana Cucu-Grosjean,et al.  Feasibility Intervals for Fixed-Priority Real-Time Scheduling on Uniform Multiprocessors , 2006, 2006 IEEE Conference on Emerging Technologies and Factory Automation.

[19]  Shelby Funk,et al.  LRE-TL: An Optimal Multiprocessor Scheduling Algorithm for Sporadic Task Sets , 2009 .

[20]  Sanjoy K. Baruah,et al.  Rate-Monotonic Scheduling on Uniform Multiprocessors , 2003, IEEE Trans. Computers.