A Performance Evaluation Tool of GALS Systems for Design Optimization

Abstract

We developed a tool for modeling GALS systems by STPN, generating incidence matrices of the STPN, and estimating a performance index through an iteration of petri-net simulations using the matrices. To reduce the cost involved in modelling GALS systems, our tool supports to draw the STPN hierachically using reusable STPN modules which model common functionalities of GALS systems. In addition, our tool can save the effort of drawing tangled arcs between modules by bundling a set of arcs which connects modules as an arc-bus. On the other hand, matrix calculation for the petri-net simulation can be accelerated by ordering of incidence matrices. The matrices are blocked into sub-matrices with respect to each module and the sub-matrices are converted to band matrices. We focus on the fact that only a part of elements in the incidence matrices are engaged in each calculation for petri-net simulation. The calculation can be further accelerated by using reference tables which dynamically hold involved elements. We applied our tool to examples and showed that the time for estimating performance indexes can be reduced up to 99.8%.