Summary: Flexible Tardiness Bounds for Sporadic Real­Time Task Systems on
Multiprocessors #
UmaMaheswari C. Devi and James H. Anderson
Department of Computer Science, The University of North Carolina at Chapel Hill
Abstract
The earliest­deadline­first (EDF) scheduling of a sporadic
real­time 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 under­
utilization 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 preemp­
tive and non­preemptive 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 con­
sider supporting tasks whose tolerances to tardiness are less
than that known to be possible under EDF. We propose a new
scheduling policy, called EDF­hl, which is a variant of EDF,

Source: Anderson, James - Department of Computer Science, University of North Carolina at Chapel Hill

Collections: Computer Technologies and Information Sciences