Utilization based schedulability bounds for age constraint process sets in real-time systems

Document type: Journal Articles
Article type: Original article
Peer reviewed: Yes
Author(s): Lars Lundberg
Title: Utilization based schedulability bounds for age constraint process sets in real-time systems
Journal: REAL-TIME SYSTEMS
Year: 2002
Pagination: 273-295
ISSN: 0922-6443
Publisher: KLUWER ACADEMIC PUBL
City: DORDRECHT
ISI number: 000177986900004
Organization: Blekinge Institute of Technology
Department: Department of Software Engineering and Computer Science (Institutionen för programvaruteknik och datavetenskap)
Dept. of Software Engineering and Computer Science S-372 25 Ronneby
+46 455 38 50 00
http://www.bth.se/eng/ipd/
Language: English
Abstract: Some real-time systems consist of a number of processes that operate under age constraints. In such systems, the maximum time from the start of process L-i in cycle k to the end in cycle k+1 must not exceed the age constraint A(i) for that process. The age constraint can be met by using fixed priority scheduling and periods equal to A(i)/2. However, this approach restricts the number of process sets which are schedulable. In this paper, we define a method for obtaining process periods other than A(i)/2. The periods are calculated in such a way that the age constraints are met. Our approach is better in the sense that a larger number of process sets can be scheduled compared to using periods equal to A(i)/2. The main results in this paper are a number of performance bounds on age constraint processes. These bounds show that there is a significant gain in worst case as well as in best case behavior by using periods other than A(i)/2, particularly when there are a large number of processes in the system.
Subject: Software Engineering\General
Keywords: age constraint, scheduling, performance bounds, harmonic periods, real-time
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