1. Introduction
The resolution of performance problems found during system testing can result in significant redesign and reworking, causing schedule delays, cost overruns and lost market opportunity. The system architecture may need to be replaced or, in the worst case, it may not be possible to build a system that meets the performance requirements at all. There is clearly a need for tools and techniques that enable performance analysis of designs to be done easily, quickly and reliably throughout the development process, in particular during the early stages of architectural and sub-system design.