I am a Ph.D. candidate at the Department of Computer Science of the University of Michigan . My advisor is Professor K. G. Shin . My thesis research evaluates this problem from both the application and the operating system perspectives. Another example, is that of the server having to serve Video frames at a certain rate to active clients. As long as the server is underloaded, keeping these commitments is easy.
Problems arise when the server becomes overloaded.
In order to provide QoS guarantees on an overloaded system it is necessary to insulate individual services from other system activties. These solutions work fine on fake workload but they don't answer the problems of managing QoS for typical applications in typical server environments. Instead of providing only control mechanisms for the insulation of services, my solution is based on a monitoring-control feedback loop. In this design the controller never presumes to know what the outcome of its control choices is. This observation-based approach can deal with changing service workload, new request arrival patterns, and dynamic interaction between disjoint application components.