SysML models: Studying safety and security measures impact on performance using graph tainting

Designing safe, secure and efficient embedded systems implies understanding interdependences between safety, security and performance requirements and mechanisms. In this paper, we introduce a new technique for analyzing the performance impact of safety/security implemented as hardware and software mechanisms and described in SysML models. Our analysis approach extracts a dependency graph from a SysML model. The SysML model is then simulated to obtain a list of simulation transactions. Then, to study the latency between two events of interest, we progressively taint the dependency graph according to simulation transactions and to dependencies between all software and hardware components. The simulation transactions are finally classified according to which vertex taint they correspond, and are displayed according to their timing and related hardware device. Thus a designer can easily spot which components need to be re-modeled in order to meet the performance requirement. A Rail Carriage use case studied in the scope of the H2020 AQUAS project illustrates our approach, in particular how tainting can handle the multiple occurrences of the same event.