Section: New Results

Component-based Design of Multi-rate Systems

Participants : Ke Sun, Jean-Pierre Talpin, Thierry Gautier, Loïc Besnard.

The Synchronous language Quartz is well suited for modeling mono-clocked systems. However, as based on the model of computation (MoC) synchrony, its parallelism feature excessively strengthens the synchronization. Such synchronous parallelism in particular restricts independent component design. That is, the modeling of connected components should constantly refer to each other to guarantee the achievement of desired system behavior. Hence, Quartz cannot support well the component-based system design, in particular for the distributed systems that are generally deployed over desynchronized processing locations with multi-rate clocks.

In contrast to Quartz, the polychronous language Signal is based on the MoC polychrony. As its name suggests, a polychronous program makes use of multi-rate clocks to drive its execution. One can consider that each component in the program holds its own master clock, and there is no longer a master clock for the whole program. The resulted architecture is named globally asynchronous locally synchronous (GALS) architecture.

Through integrating Quartz with Signal, a component-based methodology is proposed for designing multi-rate systems: at first, components are modeled independently to achieve local behaviors; secondly, inter-component communications are adjusted using Signal to realize intermittent synchronization. In this way, the modeling approach for mono-clocked systems evolves into a component-based modeling methodology. Such significant progress not only facilitates the component coordination, but also enhances the component reusability, in particular for modeling large scale systems.