A constraints programming approach to communication scheduling on SoPC architectures

This paper presents a method to obtain an optimized static schedule of CSP-like communications between a collection of concurrent hardware processes implemented on "system on a programmable chip" (SoPC). The hardware processes are the applications tailored "cells" in the processor-coupled polymorphous fabric (Wolinski et al., 2003 and Wolinski et al., 2002) implemented on the Altera Excalibur Arm SoPC platform. In our global approach, a static communications schedule is adopted to reduce hardware overhead due to inter-cells message transfer synchronization and to speed-up application execution. The scheduling problem is defined and solved using constraints programming approach. This approach makes it possible to obtain optimal communication schedules in a number of real cases. It makes also possible to easily generate pipelined schedules that improve significantly performance of the final implementation. Our method is illustrated with a fabric-based implementation of the K-means clustering algorithm. An optimal communication scheduled is achieved for this application.