A Model-Based Approach for Reconciliation of Polychronous Execution Traces

Embedded systems are very difficult to design and debug because of the limited access to the device itself. Therefore, debugging usually requires to instrument the code so as to produce execution traces that are then monitored from a base station. Such an intrusive method has a direct impact on performances. In case of multiple interacting embedded targets the problem is even more severe and is not limited to computations but also spreads to communications. To reduce the communication overhead, we propose an approach in which unsynchronized traces from several targets are reconciled a posteriori. Since each target has its own time base without a built-in clock synchronization protocol, our approach requires a multi-clock reconciliation specification. This paper describes our model-based proposal developed during the ANR project RT-Simex. The different steps of the reconciliation are illustrated on a simple case-study used in the project, a terrestrial robot controlled in position.