ARTOS: adaptive resource scheduling for component-based soft real-time applications

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Real-time systems mostly need ex ante knowledge of required resource consumptions. This is contradictory to modern usage scenarios where applications (apps) are downloaded and installed on diverse systems, and used concurrently to each other. If applications use already existing components, an exact statement of required resouces is almost impossible. Therefore, our goal is a platform that can support applications with soft real-time requirements, e.g., multimedia applications. These can be dynamically installed and used. Their ex ante unknown resource requirements on CPU time shall be fulflilled considering preferences of the end user. As implementation platform, we use real-time Java (RTSJ) and OSGi.Multiple modes of operation are added to each application. Each mode delivers different quality but also has different resource requirements. Driven by the preferences of the end user, who can favour or penalise applications, the platform takes care of a coordinated and ideal resource distribution by selecting a mode for each application. If resources are too short, less important application are degraded first, or even stopped.The scientific challenges lie in the measurment of the actually needed resources in each mode, even for previously unknown applications, in the automatic configuration of optimal modes and the dynamic adaptation of the system on changes of requirements and of available resources. Special attention is given to keeping the number of reconfigurations as low as possible and to handling periodic peak loads by phase shifts.