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Step Persistence in the Design of GALS Systems

Lookup NU author(s): Johnson Fernandes, Professor Maciej KoutnyORCiD, Dr Marta Koutny, Dr Danil Sokolov, Professor Alex Yakovlev



In this paper we investigate the behaviour of GALS (Globally Asynchronous Locally Synchronous) systems in the context of VLSI circuits. The specification of a system is given in the form of a Petri net. Our aim is to re-design the system to optimise signal management, by grouping together concurrent events. Looking at the concurrent reachability graph of the given Petri net, we are interested in discovering events that appear in "bundles", so that they all can be executed in one clock tick. The best candidates for bundles are sets of events that appear and re-appear over and over again in the same configurations, forming "persistent" sets of events. Persistence was considered so far only in the context of sequential semantics. Here we introduce a notion of persistent steps and discuss their basic properties. We then introduce a formal definition of a bundle and propose an algorithm to prune the behaviour of a system, so that only bundle steps remain. The pruned reachability graph represents the behaviour of a re-engineered system, which in turn can be implemented in a new Petri net using the standard techniques of net synthesis. The proposed algorithm prunes reachability graphs of persistent and safe nets leaving bundles that represent maximally concurrent steps.

Publication metadata

Author(s): Fernandes J, Koutny M, Pietkiewicz-Koutny M, Sokolov D, Yakovlev A

Publication type: Report

Publication status: Published

Series Title: School of Computing Science Technical Report Series

Year: 2012

Pages: 25

Print publication date: 01/08/2012

Source Publication Date: August 2012

Report Number: 1349

Institution: Newcastle University

Place Published: Newcastle upon Tyne