Section: New Results
Multiprocessor real-time scheduling
Participants : Omar Kermia, Mohamed Marouf, Yves Sorel.
We performed a lot of algorithmic and experimental work on the different theoretical results proposed last years. In particular we tested the proposed multiprocessor real-time schedulability conditions for sets of non preemptive tasks with deadline equal to period, precedence, and multiple latency constraints. Using these schedulability conditions, we proposed a back-tracking optimization heuristic which, in addition to verify the schedulability of tasks, minimizes on the one hand the total execution time (makespan) of the set of tasks running onto a multiprocessor architecture, and on the other hand the amount of memory. This heuristic which obviously gives sub-optimal results was compared to an exact algorithm giving an optimal result. All the theoretical results as well as the algorithmic and experimental results are described in  . Furthermore, they have been exploited to develop in Ocaml a new major version of SynDEx (V7) which allows the designer to specify now multiperiod applications.
Since distributed architectures are prone to failures we started a new work on fault tolerance for multiperiodic set of tasks running on a multiprocessor. This work is a follow-up of H. Kalla's former PhD thesis, which handled only monoperiodic set of tasks and simple model of fault (fail silent, transient), without sensor and actuator faults. A new PhD thesis started at the beginning of the year in collaboration with the IMARA team which wants to develop automatic control applications running on the various CyberCars platforms they develop, while providing fault tolerance. In order to tackle these complex embedded applications, we plan to study for multiperiodic set of tasks intermittent and Byzantine faults not only for the processors and the communication media, but also for the sensors and the actuators.