Timing is Key – A WCET Analysis of RTLola
Cyber-physical systems (CPS) are safety-critical, and monitoring these systems is essential to avoid dangerous situations. Therefore, the time needed between two updates in CPS must be below a speciﬁed upper bound to ensure that these systems do not produce any ﬂaws. RTLola is a stream-based speciﬁcation language for real-time constraints and is used as a monitoring language for cyber-physical systems. Worst-case execution time (WCET) analyses determine the upper bound of all possible executions on speciﬁc hardware. So far, WCET tools exist for many programming languages like Java, C++, and many more. Estimating the upper bound of one update of the monitor with such an existing tool leads to imprecise results as none of them consider the speciﬁcation being monitored. This thesis presents two approaches, which aim to compute an upper bound of the monitor using the RTLola speciﬁcation and its underlying dependencies of the streams. The ﬁrst approach focuses on the front-end of RTLola , and the second approach focuses on the analysis of the assembly code of the RTLola interpreter using the given speciﬁcation.