1 Introduction
Model-based design is increasingly emerging as the key to tackle the growing complexity of modern real-time and embedded systems. It typically involves choosing an appropriate task model which accurately reflects the characteristics of the underlying application, annotating such a model with parameters such as execution times, deadlines and periods, followed by a schedulability analysis to verify whether all timing constraints are satisfied for all possible runs of the system. For such an analysis to be meaningful, it is important to accurately estimate the execution times of the different tasks constituting the system being designed. This has led to a lot of recent work on what is referred to as the worst-case execution time (WCET) analysis of programs [5], [10], [12], [16], which involves both program path analysis and modeling the timing effects of processor microarchitectural features (e.g. caches and pipelines).