Scheduling Algorithms for Multiprogramming in a Hard-Real-Time Environment
Journal of the ACM (JACM)
IEEE Transactions on Computers
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
Flexible tardiness bounds for sporadic real-time task systems on multiprocessors
IPDPS'06 Proceedings of the 20th international conference on Parallel and distributed processing
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
Tardiness bounds under global EDF scheduling on a multiprocessor
Real-Time Systems
Generalized tardiness bounds for global multiprocessor scheduling
Real-Time Systems
Flexible tardiness bounds for sporadic real-time task systems on multiprocessors
IPDPS'06 Proceedings of the 20th international conference on Parallel and distributed processing
| Hi-index | 0.00 |
The earliest-deadline-first (EDF) scheduling of a sporadic real-time task system on a multiprocessor may require that the total utilization of the task system, Usum, not exceed (m+1)/2 on m processors if every deadline needs to be met. In recent work, we considered the alleviation of this underutilization for task systems that can tolerate deadline misses by bounded amounts (i.e., bounded tardiness). We showed that if Usum ≤ m and tasks are not pinned to processors, then the tardiness of each task is bounded under both preemptive and non-preemptive EDF. However, the tardiness bounds derived are applicable to every task in the task system, i.e., any task may incur maximum tardiness. In this paper, we consider supporting tasks whose tolerances to tardiness are less than that known to be possible under EDF. We propose a new scheduling policy, called EDF-hl, which is a variant of EDF, and show that under EDF-hl, any tardiness, including zero tardiness, can be ensured for a limited number of privileged tasks, and that bounded tardiness can be guaranteed to the remaining tasks if their utilizations are restricted. EDF-hl reduces to EDF in the absence of privileged tasks. The tardiness bound that we derive is a function of Usum, in addition to individual task parameters. Hence, tardiness for all tasks can be lowered by lowering Usum. A simulation-based evaluation of the tardiness bounds that are possible is provided.