Real-Time Scheduling Theory and Ada
Computer
Algorithms for Scheduling Imprecise Computations
Computer - Special issue on real-time systems
Scheduling Algorithms for Multiprogramming in a Hard-Real-Time Environment
Journal of the ACM (JACM)
Optimal Reward-Based Scheduling for Periodic Real-Time Tasks
IEEE Transactions on Computers
IEEE Transactions on Computers
Optimal rate-based scheduling on multiprocessors
STOC '02 Proceedings of the thiry-fourth annual ACM symposium on Theory of computing
Operating Systems Theory
A Dynamic Priority Assignment Technique for Streams with (m, k)-Firm Deadlines
IEEE Transactions on Computers
Multiprocessor Scheduling of Periodic Tasks in a Hard Real-Time Environment
IPPS '92 Proceedings of the 6th International Parallel Processing Symposium
Probabilistic performance guarantee for real-time tasks with varying computation times
RTAS '95 Proceedings of the Real-Time Technology and Applications Symposium
Skip-Over: algorithms and complexity for overloaded systems that allow skips
RTSS '95 Proceedings of the 16th IEEE Real-Time Systems Symposium
RTSS '96 Proceedings of the 17th IEEE Real-Time Systems Symposium
Integrating Multimedia Applications in Hard Real-Time Systems
RTSS '98 Proceedings of the IEEE Real-Time Systems Symposium
Statistical Rate Monotonic Scheduling
RTSS '98 Proceedings of the IEEE Real-Time Systems Symposium
Stochastic Analysis of Periodic Real-Time Systems
RTSS '02 Proceedings of the 23rd IEEE Real-Time Systems Symposium
Priority-Driven Scheduling of Periodic Task Systems on Multiprocessors
Real-Time Systems
Static-Priority Scheduling on Multiprocessors
RTSS '01 Proceedings of the 22nd IEEE Real-Time Systems Symposium
Multiprocessor EDF and Deadline Monotonic Schedulability Analysis
RTSS '03 Proceedings of the 24th IEEE International Real-Time Systems Symposium
IEEE Transactions on Computers
Real Time Scheduling Theory: A Historical Perspective
Real-Time Systems
An EDF-based Scheduling Algorithm for Multiprocessor Soft Real-Time Systems
ECRTS '05 Proceedings of the 17th Euromicro Conference on Real-Time Systems
An Upper Bound to the Lateness of Soft Real-Time Tasks Scheduled by EDF on Multiprocessors
RTSS '05 Proceedings of the 26th IEEE International Real-Time Systems Symposium
Tardiness Bounds under Global EDF Scheduling on a Multiprocessor
RTSS '05 Proceedings of the 26th IEEE International Real-Time Systems Symposium
Analysis of a window-constrained scheduler for real-time and best-effort packet streams
RTSS'10 Proceedings of the 21st IEEE conference on Real-time systems symposium
Worst-case utilization bound for EDF scheduling on real-time multiprocessor systems
Euromicro-RTS'00 Proceedings of the 12th Euromicro conference on Real-time systems
Journal of Experimental Algorithmics (JEA)
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There has been much recent interest in the use of the earliest-deadline-first ( $\mathsf{EDF}$ ) algorithm for scheduling soft real-time sporadic task systems on identical multiprocessors. In hard real-time systems, a significant disparity exists between $\mathsf{EDF}$ -based schemes and Pfair scheduling: on M processors, the worst-case schedulable utilization for all known $\mathsf{EDF}$ variants is approximately M/2, whereas it is M for optimal Pfair algorithms. This is unfortunate because $\mathsf{EDF}$ -based algorithms entail lower scheduling and task-migration overheads. However, such a disparity in schedulability can be alleviated by easing the requirement that all deadlines be met, which may be sufficient for soft real-time systems. In particular, in recent work, we have shown that if task migrations are not restricted, then $\mathsf{EDF}$ (i.e. , global $\mathsf{EDF}$ ) can ensure bounded tardiness for a sporadic task system with no restrictions on total utilization. Unrestricted task migrations in global $\mathsf{EDF}$ may be unappealing for some systems, but if migrations are forbidden entirely, then bounded tardiness cannot be guaranteed. In this paper, we address the issue of striking a balance between task migrations and system utilization by proposing an algorithm called $\mathsf{EDF-fm}$ , which is based upon $\mathsf{EDF}$ and treads a middle path, by restricting, but not eliminating, task migrations. Specifically, under $\mathsf{EDF-fm}$ , the ability to migrate is required for at most M驴1 tasks, and it is sufficient that every such task migrate between two processors and at job boundaries only. $\mathsf{EDF-fm}$ , like global $\mathsf{EDF}$ , can ensure bounded tardiness to a sporadic task system as long as the available processing capacity is not exceeded, but, unlike global $\mathsf{EDF}$ , may require that per-task utilizations be capped. The required cap is quite liberal, hence, $\mathsf{EDF-fm}$ should enable a wide range of soft real-time applications to be scheduled with no constraints on total utilization.