Synchronous dataflow (SDF) is a special case of dataflow where the flow of control is sufficiently regular to be completely predictable at compile time. An SDF model is an interconnection of actors whose firings are enabled by fixed, pre-specified numbers of tokens on each of their inputs. Moreover, when an actor fires, it produces a fixed, pre-specified number of tokens on each of its outputs. The fact that these numbers are fixed makes it possible for a scheduler to determine the firing sequence at the time the model is initialized. Thus, SDF models are quite efficient, in that there is no multithreading needed, and run-time overhead consists only of a very simple dispatcher that implements the pre-computed schedule.
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