Providing Configurable QoS Management in Real-Time Systems with QoS Aspect Packages

Current quality of service (QoS) management approaches in real-time systems lack support for configurability and reusability as they cannot be configured for a target application or reused across many applications. In this paper we present the concept of a QoS aspect package that enables developing configurable QoS management for real-time systems. A QoS aspect package represents both the specification and the implementation of a set of aspects and components that provide a number of QoS policies. A QoS aspect package enables upgrades of already existing systems to support QoS performance assurance by adding aspects and components from the package. Furthermore, a family of real-time systems can easily be developed by adding aspects from the QoS aspect package into an existing system configuration. We illustrate the way a family of real-time database systems is developed using the QoS aspect package with a case study of an embedded real-time database system, called COMET. Our experiments with the COMET database have shown that it is indeed possible to design a real-time system without QoS management and then with a reasonable effort add the QoS dimension to the system using a QoS aspect package.