Incremental Analysis of Cyclo-Static Synchronous Dataflow Graphs

In this article, we present a mathematical characterisation of admissible schedules of cyclo-static dataflow (<scp>csdf</scp>) graphs. We demonstrate how algebra ic manipulation of this characterization is related to unfolding <scp>csdf</scp> actors and how this manipulation allows <scp>csdf</scp> graphs to be transformed into <scp>mrsdf</scp> graphs that are <i>equivalent</i>, in the sense that they admit the same set of schedules. The presented transformation allows the rich set of existing analysis techniques for <scp>mrsdf</scp> graphs to be applied to <scp>csdf</scp> graphs and generalizes the well-known transformations from <scp>csdf</scp> and <scp>mrsdf</scp> into <scp>hsdf</scp>. Moreover, it gives rise to an incremental approach to the analysis of <scp>csdf</scp> graphs, where approximate analyses are combined with exact transformations. We show the applicability of this incremental approach by demonstrating its effectiveness on the problem of optimizing buffer sizes under a throughput constraint.