Experiences from Applying WCET Analysis in Industrial Settings

Knowing the program timing characteristics is fundamental to the successful design and execution of real-time systems. Today, measurement-based timing analysis tools such as in-circuit emulators, logic analyzers and oscilloscopes, are used in industry. A critical timing measure is the worst-case execution time (WCET) of a program. Recently, tools for deriving WCET estimates, mostly based on static program analysis, have reached the market. In this article, we summarize experiences from five different industrial case-studies. The studies were made on typical industrial systems, in close cooperation with the system developers, using both static and measurement-based tools. The primary purpose was to investigate the difficulties involved in applying current timing analysis methods to industrial code. We were also interested how WCET estimates can be derived by different methods, how labor-intensive the methods are, and the accuracy of obtained results. As a result, we provide observations on the benefits and drawbacks of the different timing analysis methods used and specify general conditions when a particular method should be most beneficial. We also show the benefits of having several types of timing analysis tools available