10 A Constraint-based Approach to Cyclic Resource-Constrained Scheduling Problem

The cyclic schedulingproblem concerns assigningstart times toaset of activities, to be indefinitely repeated, subject to precedence and resource constraints. It can be found in many application areas. For instance, it arises in compiler design implementing loops on parallel architecture[5], and on data-flow computations in embedded applications[2]. Moreover, cyclic scheduling can be found in mass production, such as cyclic shop or Hoist scheduling problems[6]. In cyclic scheduling often the notion of optimality is related to the period of the schedule. A minimal period corresponds to the highest number of activities carried out on average over a large time window. Optimal cyclic schedulers are lately in great demand, as streaming paradigms are gaining momentum across a wide spectrum of computing platforms, ranging from multi-media encoding and decoding in mobile and consumer devices, to advanced packet processing in network appliances, to high-quality rendering in game consoles. In stream computing, an application can be abstracted as a set of tasks that have to be performed on incoming items (frames) of a data stream