Main Menu/Search/Help
PUBLICATIONS of the DSP DESIGN GROUP and the PTOLEMY PROJECT
A Comparison of Synchronous and Cyclo-Static Dataflow
Asilomar Conference on Signals, Systems, and Computers
October 1995
Thomas M. Parks, José Luis Pino and Edward A. Lee
Abstract
We compare synchronous dataflow (SDF) and cyclo-static dataflow
(CSDF), which are each special cases of a model of computation we call
dataflow process networks. In SDF, actors have static firing rules:
they consume and produce a fixed number of data tokens in each
firing. This model is well suited to multirate signal processing
applications and lends itself to efficient, static scheduling,
avoiding the run-time scheduling overhead incurred by general
implementa-tions of process networks. In CSDF, which is a
generaliza-tion of SDF, actors have cyclicly changing firing rules. In
some situations, the added generality of CSDF can unnec-essarily
complicate scheduling. We show how higher-order functions can be used
to transform a CSDF graph into a SDF graph, simplifying the scheduling
problem. In other situations, CSDF has a genuine advantage over SDF:
sim-pler precedence constraints. We show howthis makes it pos-sible to
eliminate unnecessary computations and expose ad-ditional
parallelism. We use digital sample rate conversion as an example to
illustrate these advantages of CSDF.
![[PDF]](../icons/PDF.gif){kind=icon}
![[Postscript]](../icons/Postscript.gif){kind=icon}