NCS calculation method for streaming applications

Our contribution in the context of the "Quality of Service (QoS) in IN-home digital networks" project was focused on the QoS provided by consumer electronics terminals. In order to achieve a particular level of QoS provided by a terminal, an important issue is resource management supported by performance analysis. The work we present in this article is highlighting ways of predicting the necessary resources (e.g. CPU, memory, bus) needed by a video streaming application to provide a given level of QoS. We introduce a calculation method that involves measuring in isolation the resource needs of each of the individual streaming components, and also a performance composition analysis, which takes into account the Number of Context Switches (NCS) occurring during the execution of the application. We based our calculation for the NCS on the observation that running streaming applications, eventually adopt a pattern of execution that repeats after a specific interval of time (hyperperiod). By finding the NCS induced during a hyperperiod, we deduce the total NCS occurring during the execution of the application. The article gives a characterization of the streaming applications execution and of the component model that lie at the basis of our calculation