The goal of this project is to develop theory and methods for timing analysis, especially WCET analysis, of component-based systems. Timing properties are important in real-time systems, and any component technology for software development of such systems must have some means to estimate the timing behaviour. Depending on the kind of real-time constraints, either approximate or absolute upper bounds for the execution time are needed.
Timing analysis of component-based systems naturally divides into two distinct parts: intra-component analysis, and inter-component analysis. The first part concerns possible execution times of tasks executing code fully contained within a component, and the second part concerns tasks which execute code from different components. We will study both parts, in two subprojects.
Components are typically designed to be reusable. Thus, they are likely to exhibit a highly parameterized timing behaviour, where execution time bounds depend heavily on input parameters to the component. In the first subproject, we will therefore develop methods for parametric timing analysis where the execution time bounds are expressed as a formula in some parameters rather than a single number.
When components are composed into systems, it may well happen that the code of some components is not available: they may, for instance be commercial components where license agreements forbid reverse-engineering of the code. However, the vendor may have analyzed the component before shipping it, and may have shipped also the analysis results. A composable analysis could then take the analysis results for individual components, and produce inter-component execution time bounds. Thus, the second, inter-component analysis subproject will focus on the issue of ai>composability of timing analysis.
Sequential Composition of Execution Time Distributions by Convolution (Nov 2011) Marcelo Santos, Björn Lisper, George Lima , Veronica Lima Proc. 4th Workshop on Compositional Theory and Technology for Real‐Time Embedded Systems (CRTS 2011)
Fully-Automatic Derivation of Exact Program-Flow Constraints for a Tighter Worst-Case Execution-Time Analysis (Jul 2011) Amine Marref Proceedings of the 11th IEEE International Conference on Embedded Computer Systems: Architectures, Modeling, and Simulation (SAMOS XI)
Deriving WCET Bounds by Abstract Execution (Jul 2011) Andreas Ermedahl, Jan Gustafsson, Björn Lisper Proc. 11th International Workshop on Worst-Case Execution Time (WCET) Analysis (WCET 2011)
An Efficient Algorithm for Parametric WCET Calculation (May 2011) Stefan Bygde, Andreas Ermedahl, Björn Lisper Journal of Systems Architecture
WCET Analysis of Component-Based Systems using Timing Traces (Apr 2011) Adam Betts, Amine Marref Proceedings of the 16th IEEE International Conference on Engineering of Complex Computer Systems (ICECCS 2011)