Efficient Monitoring of Embedded Real-Time Systems
- J. Cadamuro
- Fifth International Conference on Information…
“The estimation of the Worst Case Execution Time of a function produces results that are safe and that have a low error, even in architectures using pipelines and caches.” This is our thesis; in this paper we present results that indicate that this thesis is correct. The two basic approaches to obtain WCET of a piece of code are estimation and measurement. At LIT, a tool called PERF is under development. This tool uses both approaches so to obtain the best of both worlds. Measurement provides precise results, but requires the target to be built and running the worst possible scenario, which is often hard to determine. On the other hand, the precision of estimation methods is highly dependent on the complexity of the estimation model. PERF is a design and evaluation environment: a project can be defined, files can be edited, compiled, linked; the resulting code can be analyzed from a timing perspective both via estimation and via measurement. In this way, we intend to encourage the developer to perform time estimations as early as possible in the design cycle. Any tool (commercial or academic) can be inserted in PERF via plug-ins. This was the case of the text editor, the compiler and the linker. Hence, PERF is actually a framework to which many tools can be added. PERF works with the object code generated by the integrated tools, in order to obtain execution time limit estimations for functions that compose a real-time systems’ software project. In this paper we present the PERF environment’s architecture, with emphasis on the integrated time estimation model and the results obtained using this model.