Out-Of-order execution of synchronous data-flow networks

Data flow process networks (DPNs) have been introduced as a convenient model of computation for distributed and asynchronous systems since each process node can work independently of the other nodes, i. e. without the need of a global coordination. Synchronous and cyclo-static data flow process networks even allow to derive at compile-time efficient static schedules that allow one to run these systems with an efficient use of available resources, e. g. in embedded systems. Single process nodes of DPNs are stream-based computing devices that transform input streams to uniquely defined corresponding output streams such that single values of the output streams are computed as soon as sufficient input values are available. In this sense, they are related to the execution of an instruction stream by a conventional microprocessor. In this paper, we show how out-of-order execution that has been introduced for the efficient use of multiple functional units in microprocessors can also be used for the implementation of DPNs on multiprocessors. This way, the implementation of DPNs on multiprocessors allows one to optimize the throughput of single process nodes, and as shown by our experiments, also of the entire DPN.