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Generalized performance management of multi-class real-time imprecise data services
Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
Software Engineering Institute, Carnegie Mellon University, USA.
Dept. of Computer Science, University of Virginia, Charlottesville, USA.
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2005 (English)In: Real-Time Systems Symposium, 2005. RTSS 2005. 26th IEEE International, 2005, 12-49 p.Conference paper, Published paper (Other academic)
Abstract [en]

The intricacy of real-time data service management increases mainly due to the emergence of applications operating in open and unpredictable environments, increases in software complexity, and need for performance guarantees. In this paper we propose an approach for managing the quality of service of real-time databases that provide imprecise and differentiated services, and that operate in unpredictable environments. Transactions are classified into service classes according to their level of importance. Transactions within each service class are further classified into subclasses based on their quality of service requirements. In this way transactions are explicitly differentiated according to their importance and quality of service requests. The performance evaluation shows that during overloads the most important transactions are guaranteed to meet their deadlines and that reliable quality of service is provided even in the face of varying load and execution time estimation errors.

Place, publisher, year, edition, pages
2005. 12-49 p.
Keyword [en]
real-time system, database, QoS, feedback control
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:liu:diva-12638DOI: 10.1109/RTSS.2005.23OAI: oai:DiVA.org:liu-12638DiVA: diva2:16751
Available from: 2007-10-17 Created: 2007-10-17 Last updated: 2009-04-22
In thesis
1. QoS Control of Real-Time Data Services under Uncertain Workload
Open this publication in new window or tab >>QoS Control of Real-Time Data Services under Uncertain Workload
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Real-time systems comprise computers that must generate correct results in a timely manner. This involves a wide spectrum of computing systems found in our everyday life ranging from computers in rockets to our mobile phones. The criticality of producing timely results defines the different types of realtime systems. On one hand, we have the so-called hard real-time systems, where failing to meet deadlines may result in a catastrophe. In this thesis we are, however, concerned with firm and soft real-time systems, where missing deadlines is acceptable at the expense of degraded system performance. The usage of firm and soft real-time systems has increased rapidly during the last years, mainly due to the advent of applications in multimedia, telecommunication, and e-commerce. These systems are typically data-intensive, with the data normally spanning from low-level control data, typically acquired from sensors, to high-level management and business data. In contrast to hard real-time systems, the environments in which firm and soft real-time systems operate in are typically open and highly unpredictable. For example, the workload applied on a web server or base station in telecommunication systems varies according to the needs of the users, which is hard to foresee. In this thesis we are concerned with quality of service (QoS) management of data services for firm and soft real-time systems. The approaches and solutions presented aim at providing a general understanding of how the QoS can be guaranteed according to a given specification, even if the workload varies unpredictably. The QoS specification determines the desired QoS during normal system operation, and the worst-case system performance and convergence rate toward the desired setting in the face of transient overloads. Feedback control theory is used to control QoS since little is known about the workload applied on the system. Using feedback control the difference between the measured QoS and the desired QoS is formed and fed into a controller, which computes a change to the operation of the real-time system. Experimental evaluation shows that using feedback control is highly effective in managing QoS such that a given QoS specification is satisfied. This is a key step toward automatic management of intricate systems providing real-time data services.

Place, publisher, year, edition, pages
Institutionen för datavetenskap, 2007. 244 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1143
Keyword
real-time system, database, feedback control
National Category
Computer Science
Identifiers
urn:nbn:se:liu:diva-10016 (URN)978-91-85895-49-6 (ISBN)
Public defence
2007-11-15, Planck, Fysikhuset, Linköpings universitet, 13:15 (English)
Opponent
Supervisors
Available from: 2007-10-17 Created: 2007-10-17 Last updated: 2009-04-22

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Amirijoo, MehdiHansson, JörgenGunnarsson, Svante

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Citation style
  • apa
  • harvard1
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Output format
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