Time-Predictable Reconfiguration with Contract-Based Resource Management

Applications of high-quality multimedia embedded systems (HQMES) contain concurrent functionality pieces; they may have a flexible structure consisting of services, components, or tasks. This allows applications to offer different execution possibilities to provide a same (or different) output quality. Since multimedia applications are typically greedy resource consumers, they may interfere one another´s execution; this can be a source of unpredictability, especially in the event of reconfigurations. This paper presents a description on how to minimize such execution uncertainty at different levels: (1) the OS has to offer the basic real-time support, (2) appropriate resource management techniques will have to be built, usually inside a QoSRM (QoS resource manager entity), and (3) applications should be designed in a flexible but yet manageable way. This paper recovers an efficient application characterization as the basis for offering the QoSRM a manageable application structure. On top of this application characterization, a contract model is described to provide predictable execution. Also, two reconfiguration algorithms are presented, so that application execution is kept predictable even during reconfiguration.