Call String Sensitivity for Hardware-Based Hybrid WCET Analysis
Boris Dreyer, Christian Hochberger, Simon Wegener · IEEE Embedded Systems Letters · 2021
Many embedded systems operate under real-time conditions. For them, the worst case execution time (WCET) is a crucial information to check whether the software implementation meets the requirements. In modern microcontrollers, this WCET can often no longer be evaluated statically since these processors include too many unpredictable components (cache, bus arbitration,$\ldots$,). Here, hybrid WCET estimation comes into play, where measured traces are used to empirically compute bounds for the WCET. For meaningful estimations, it is required to put each measured segment into a corresponding execution context. In this contribution, we present a method that allows to gather such context-sensitive statistics online in hardware. This enables arbitrary long measurement intervals with a precision that compares to state-of-the-art offline tools.