On-line schedulability tests for adaptive reservations in fixed priority scheduling
Författare
Summary, in English
Adaptive reservation is a real-time scheduling technique in which each application is associated a fraction of the computational resource (a reservation) that can be dynamically adapted to the varying requirements of the application by using appropriate feedback control algorithms. An adaptive reservation is typically implemented by using an aperiodic server (e.g. sporadic server) algorithm with fixed period and variable budget. When the feedback law demands an increase of the reservation budget, the system must run a schedulability test to check if there is enough spare bandwidth to accommodate such increase. The schedulability test must be very fast, as it may be performed at each budget update, i.e. potentially at each instance of a task; yet, it must be as efficient as possible, to maximize resource usage. In this paper, we tackle the problem of performing an efficient on-line schedulability test for adaptive resource reservations in fixed priority schedulers. In the literature, a number of algorithms have been proposed for on-line admission control in fixed priority systems. We describe four of these tests, with increasing complexity and performance. In addition, we propose a novel on-line test, called Spare-Pot algorithm, which has been specifically designed for the problem at hand, and which shows a good cost/performance ratio compared to the other tests.
Avdelning/ar
Publiceringsår
2012
Språk
Engelska
Sidor
601-634
Publikation/Tidskrift/Serie
Real-Time Systems
Volym
48
Issue
5
Dokumenttyp
Artikel i tidskrift
Förlag
Springer
Ämne
- Control Engineering
Nyckelord
- Resource reservation
- Adaptive scheduling
- Fixed priority
Status
Published
Forskningsgrupp
- LCCC
ISBN/ISSN/Övrigt
- ISSN: 1573-1383