Temporal isolation in real-time systems: the VBS approach

• Published in: International journal on software tools for technology transfer 2013-06, Vol.15 (3), p.189-209
• Main Authors: Craciunas, Silviu S., Kirsch, Christoph M., Payer, Hannes, Röck, Harald, Sokolova, Ana
• Format: Article
• Language: English
• Subjects: Accounting; Algorithms; Computer programs; Computer Science; Embedded systems; Eurosys; Power consumption; Real time; Scheduling; Scheduling algorithms; Servers; Software; Software Engineering; Software Engineering/Programming and Operating Systems; Systems design; Temporal logic; Theory of Computation
• ISSN: 1433-2779; 1433-2787
• DOI: 10.1007/s10009-012-0246-x

Temporal isolation in real-time systems allows the execution of software processes isolated from one another in the temporal domain. Intuitively, the execution of a process is temporally isolated if the real-time behavior of the process is independent of the execution of the other concurrently scheduled processes in the system. The article provides a comprehensive discussion of temporal isolation through variable-bandwidth servers (VBSs). VBS consists of an EDF-based uniprocessor scheduling algorithm and a utilization-based schedulability test. The scheduling algorithm runs in constant time modulo the time complexity of queue management. The schedulability test runs in time linear in the number of processes and enables admission of an individual process in constant time. The test is a sufficient condition for VBS to provide temporal isolation through lower and upper response-time bounds on processes. We present the VBS design, implementation, proofs, and experiments, followed by condensed versions of results on scheduler overhead accounting with VBS and on reducing power consumption in VBS systems.