DynaQoS©-RDF : a best effort for QoS-assurance of dynamic reconfiguration of dataflow systems

The significance of QoS-assurance is being increasingly recognized by both the research and wider communities. In the latter case, this recognition is driven by the increasing adoption by business of 24/7 software systems and the QoS decline that end-users experience when these systems undergo dynamic reconfiguration. At the beginning of 2006, the author set up a project named DynaQoS©-RDF (QoS-assurance of Dynamic Reconfiguration on Reconfigurable Dataflow Model), which was then sponsored by the CQ University Australia. Over the last two years, the author has investigated QoS-assurance for dataflow systems, which are characterized by the pipe-and-filter architecture. The research has addressed issues such as: the global consistency of protocol transactions, the necessary and sufficient conditions for QoS-assurance, execution overhead control for reconfiguration, state transfer for stateful components, and the design of a QoS benchmark. This paper discusses these research issues. It also proposes various QoS strategies and presents a benchmark for evaluating QoS-assurance strategies for the dynamic reconfiguration of dataflow systems. This benchmark is implemented using the DynaQoS©-RDF v1.0 software platform. Various strategies, including those from the research literature are benchmarked, and the best efforts for QoS-assurance are identified.