ABBs: Atomic Basic Blocks

Motivation

In the normal case, real-time computing systems have to handle one or more events in a timely manner. Depending on the particular application event handlers can process these events either in isolation or in a cooperative way. As soon as the handling of an event is carried out in cooperation of one or more event handlers, these event handlers have to be coordinated in order to obey e.g. input/output dependencies. This means dependencies among different event handlers have to be established. The methods to establish dependencies, however, differ a lot in time-triggered and event-triggered systems. In time-triggered systems the focus is on calculating an appropriate schedule offline that meets these dependencies implicitly. Though, usually this is not possible with event-triggered systems and explicit means are required to ensure e.g. mutual exclusion. These different approaches also impose quite different execution semantics - on the one hand run-to-completion semantics is employed in time-triggered systems whereas event handlers can also block in event-triggered systems - making the exchange of application code between time-triggered and event-triggered systems laborious. Thus, this research project deals with the extraction of such dependencies from existing applications and the conversion between their explicit and implicit representations.

Major Goals and Questions

The ambitious goal of this research project is to provide an (semi-)automativ conversion of dependencies that are explicitly established within event-triggered systems into implicit dependencies prevalent in time-triggered systems.