Deadlock risk assessment in architectural models of real-time systems

Software architectural assessment is a key discipline to identify at early stages of a system synthesis the problems that may become critical in its operation. This matter is especially relevant for those systems with real-time constraints. In this paper a special emphasis shall be made on concurrency issues. Typical mechanisms supporting concurrency, such as semaphores or monitors, usually lead to concurrency problems in execution time hard to identify, reproduce and solve. For this reason it is crucial to understand the root causes of these problems and to provide support to identify and mitigate them at early stages of the system lifecycle. This paper aims to present the results of a research work oriented to the creation of a tool to assess deadlock risk in architectural models. A concrete architectural style (PPOOA-UML) was used as a reference to represent system models supported by the PPOOA-Visio CASE tool. In addition a case study was used to validate a deadlock assessment tool created for an on-going research work. In the context of one of the functions of a military transport aircraft, the auto-tuning function of the communications system was selected for the assessment of the deadlock risk. According to the results obtained, some guidelines are outlined to minimize deadlock risk of the example architecture.