Incremental Analysis of Cyclo-Static Synchronous Dataflow Graphs

In this article, we present a mathematical characterisation of admissible schedules of cyclo-static dataflow (CSDF) graphs. We demonstrate how algebra ic manipulation of this characterization is related to unfolding CSDF actors and how this manipulation allows CSDF graphs to be transformed into MRSDF graphs that are equivalent, in the sense that they admit the same set of schedules. The presented transformation allows the rich set of existing analysis techniques for MRSDF graphs to be applied to CSDF graphs and generalizes the well-known transformations from CSDF and MRSDF into HSDF. Moreover, it gives rise to an incremental approach to the analysis of CSDF 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.