Section: New Results

Real-time scheduling and code generation for time-triggered platforms

Participants : Dumitru Potop Butucaru, Thomas Carle, Raul Gorcitz, Yves Sorel.

We have continued this year the work on real-time scheduling and code generation for time-triggered platforms. Much of this work was carried out as part of a bilateral collaboration with Airbus DS and the CNES, which fund the post-doctorate of Raul Gorcitz, and in our collaboration with the IRT SystemX, project FSF.

The objective is to facilitate the development of complex time-triggered systems by automating the allocation, scheduling, and code generation steps. We show that full automation is possible while taking into account all the specification elements required by a complex, real-life embedded control system. The main originality of our work is that it takes into account at the same time multiple complexity elements: functional specifications with conditional execution and multiple modes and various types of non-functional properties: real-time (release dates, deadlines, major time frame, end-to-end flows), ARINC 653 partitioning (which we can fully or partially synthesize), task preemptability, allocation. Our algorithms allow the automatic allocation and scheduling onto multi-processor (distributed) systems with a global time base, taking into account communication costs.

While the past years were mainly dedicated to the development of this scheduling and code generation technique, this year the technique and the associated tool have matured enough to allow the publication of the first results concerning the optimized scheduling algorithms [21] and its application on large case studies. Ongoing work by the post-doc Raul Gorcitz, funded by Airbus DS and the CNES aims at evaluating the applicability of our methods on embedded platforms that are being considered for the future european space launchers. The Lopht tool is also used in the IRT SystemX, project FSF as part of the proposed design flow. All extensions have been implemented in the Lopht tool. All this work has been presented in extenso in the PhD thesis of Thomas Carle [16] .