Introduction

I will talk about the difficult or currently unsolved problems in WCET analysis, both for the static-analysis tools and the measurement-based tools (which of course have to some extent different problems), why we can expect these problems to remain hard, and also can expect that new hard problems will appear. Of course this talk is intended to be provocative rather than blackly pessimistic, so I hope to give some pointers to possible solutions or work-arounds, as future research directions. But I do not promise to be optimistic...

Summary

• WCET analysis is practical now only for relatively simple programs on relatively simple microcontrollers.
  However, "simple" does not imply "small".
• Current applications are in highly critical systems: aerospace, automotive, nuclear.
• Static analysis of worst-case processor behaviour seems hopeless for high-end, general processors. Open question: are predictable but powerful processors possible?
• Measurement-based analysis is unreliable for the same reasons, but is more reliable than end-to-end measurements.
• Control-flow analysis has promising problems to work on.
• Increased use of static analysis for bug-finding and the like may push programs to be more analysable.
• Existence of WCET tools pushes the state of the art, which may make WCET analysis required for critical SW.

Slides: PDF, OpenOffice.org source.