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RTCSA
1999
IEEE

Scheduling Fixed-Priority Tasks with Preemption Threshold

10 years 3 months ago
Scheduling Fixed-Priority Tasks with Preemption Threshold
While it is widely believed that preemptability is a necessary requirement for developing real-time software, there are additional costs involved with preemptive scheduling, as compared to non-preemptive scheduling. Furthermore, in the context of fixed-priority scheduling, feasibility of a task set with nonpreemptive scheduling does not imply feasibility with preemptive scheduling (and vice-versa). In this paper, we use the notion of preemption threshold to develop a new scheduling model, which unifies the concepts of preemptive and non-preemptive scheduling, and subsumes both as special cases. The notion of preemption threshold was introduced by Express Logic, Inc. in their ThreadX real-time operating system. It allows a task to disable preemption from tasks up to a specified threshold priority. Tasks having priorities higher than the threshold are still allowed to preempt. In our new model, each task has a regular priority and a preemption threshold. We show how the new scheduling m...
Yun Wang, Manas Saksena
Added 04 Aug 2010
Updated 04 Aug 2010
Type Conference
Year 1999
Where RTCSA
Authors Yun Wang, Manas Saksena
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