Flexible tardiness bounds for sporadic real-time task systems on multiprocessors

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 nu...

• Type: Conference
• Year: 2006
• Where: IPPS
• Authors: UmaMaheswari C. Devi, James H. Anderson
• Keywords: Distributed And Parallel Computing, IPPS 2006, Sporadic Real-time Task, Tardiness Bounds, Task System