Scheduling Dependent Periodic Tasks Without Synchronization Mechanisms

Julien Forget (1) , Frédéric Boniol (2, 3) , Emmanuel Grolleau (4) , David Lesens (5) , Claire Pagetti (2, 3)

1 LaBRI - Laboratoire Bordelais de Recherche en Informatique
2 ONERA - The French Aerospace Lab [Toulouse]
3 ENSEEIHT - Ecole Nationale Supérieure d'Electrotechnique, d'Electronique, d'Informatique, d'Hydraulique et de Télécommunications
4 LISI [Poitiers] - Laboratoire d'informatique scientifique et industrielle [EA 1232]
5 AST - Astrium Space Transportation

This article studies the scheduling of critical embedded systems, which consist of a set of communicating periodic tasks with constrained deadlines. Currently, tasks are usually sequenced manually, partly because available scheduling policies do not ensure the determinism of task communications. Ensuring this determinism requires scheduling policies supporting task precedence constraints (which we call dependent tasks), which are used to force the order in which communicating tasks execute. We propose fixed priority scheduling policies for different classes of dependent tasks: with simultaneous or arbitrary release times, with simple precedences (between tasks of the same period) or extended precedences (between tasks of different periods). We only consider policies that do not require synchronization mechanisms (like semaphores). This completely prevents deadlocks or scheduling anomalies without requiring further proofs.

Domaines: Systèmes embarqués

Julien Forget, Frédéric Boniol, Emmanuel Grolleau, David Lesens, Claire Pagetti. Scheduling Dependent Periodic Tasks Without Synchronization Mechanisms. 16th IEEE Real-Time and Embedded Technology and Applications Symposium, Apr 2010, Stockholm, Sweden. pp.301--310. ⟨hal-00800980⟩