WCET analysis of the µC/OS-II real-time kernel

Worst-case execution time (WCET) analysis is one of the major tasks in timing validation of hard real-time sys-tems. In complex systems with real-time operating systems (RTOS), the timing properties of the system are decided by both the applications and the RTOS. Traditionally, WCET analysis mainly deals with application programs, while it is crucial to know whether the RTOS also behaves in a timely predictable manner. In this paper, we present a case study where static analysis is used to predict the WCET of the system calls of the µC/OS-II real-time kernel. To our knowl-edge, this paper is the first to present quantitative results on the real-time performance of µC/OS-II. The precision of ap-plying existing WCET analysis techniques on RTOS code is evaluated, and the practical difficulties in using static meth-ods in timing analysis of RTOS are also reported. 1