Cheddar : about the usability of the real-time scheduling theory Ellidiss Technologies, France University of Brest/UBO, Lab-STICC/UMR 6285, France

2/18 Talk overview 1.Cheddar project : context and motivations 2.Research Roadmap

3/17 About scheduling analysis and its use  Real-time scheduling theory:  Simplified models of functions : e.g. periodic task: processor demand + deadline.  Analysis: either with feasibility tests or simulations. 1.Scheduling Simulation: 2.Feasibility tests : => architectures must meet assumptions of the feasibility test.

4/17 Does people really use real-time scheduling theory ? – Real-time scheduling theory, verification with analytical methods and/or simulations: 1. Most important theoretical results proposed between 1974 and 1994 (simple uniprocessor architectures). 2. Technologies are compliant with (POSIX b operating systems, Ada/Ravenscar profile, …). 3. Strong demand from engineers. 4. … Not used as much we can expect 

5/17 Some possible explanations 1.This theory can not be applied on some architecture types (e.g. multiprocessor/distributed/hierarchical systems). 2.Require advanced skills to be used: – Numerous theoretical results: how to choose the right one ? – Numerous assumptions for each result. – How to abstract/model a system to access schedulability ? (e.g. dependency) 3.Engineers must be helped to use tools: – How and when performing this analysis ? – How to write models to be analyzed ? Which design languages ? – How to safely use scheduling tools ? 4....

6/18 Talk overview 1.Cheddar project : context and motivations 2.Research Roadmap

7/18 – Cheddar project : expects to increase the usability of the real-time scheduling theory. Started in 2002 by Univ. of Brest, partnership with Ellidiss Tech. (provide open source and industrial support) since Current project members (U. Brest & Ellidiss Tech.) : A. Plantec, S. Rubini, V. Gaudel, P. Dissaux, J. Legrand, J. Boukhobza, L. Lemarchand, C Fotsing, S. Li, I. Armah-mensah, N. Tran Hai and F. Singhoff. Support : Ellidiss Tech., Conseil Régional de Bretagne, BMO, EGIDE/Campus France, Thalès communication. Other contributors/partners: Télécom-Paris-Tech, ISAE, Univ. Lisboa Cheddar project : context and motivations

Cheddar 3.0 new features Distributed with the next AADLInspector releases: ◦ Extended Cheddar ADL for multiprocessor and hierarchical architectures, new generated XML printer/parser (A. Plantec, C. Fotsing, F. Singhoff) ◦ Design pattern uniprocessor analysis tool (Phd Gaudel, A. Plantec, P. Dissaux, F. Singhoff) ◦ Global multiprocessor scheduling : global RM/DM/EDF/LLF, Pfair scheduling (F. Singhoff) ◦ New 2-levels scheduling services : various aperiodic servers and cyclic 2-levels schedulers (F. Singhoff) ◦ New ARINC 653 features : scheduling + feasibility test + export of ARINC 653 configuration table (A. Plantec, F. Singhoff, P. Dissaux, Phd V. Gaudel)

Cheddar 3.1 new features Ongoing developments : ◦ N-levels hierarchical scheduling analysis, both analytic and scheduling simulation (Phd V. Gaudel, P. Dissaux, A. Plantec, F. Singhoff) ◦ Task group based support : (Phd S. Li, V. Nguyen, S. Rubini, F. Singhoff)  Offset worst case response time analysis tools  GMF/MF task scheduling simulation support + transformation ◦ Analysis of Multicore architectures with caches (scheduling simulation) and with extended task semantics /AADL BA (S. Rubini, N. Tran, F. Singhoff) ◦ New machine man interface (C. Fotsing, F. Singhoff)

Cheddar 3.1 new features Future developments (starting fall 2013): ◦ Memory hierarchy (including cache) and scheduling analysis (Phd N. Tran, S. Rubini, J. Boukhoza, F. Singhoff) ◦ Modeling and automatic code generation of partitionning algorithms (Phd I. Armah Mensah, JP Babau, F. Singhoff) ◦ RTEMS source code generation and comparison with Cheddar verification (C. Fotsing) ◦ SMART project (June 2014) ◦ U. Lisbonne/SAPIENT 2 (2014/2016). Bus scheduling and tasks scheduling/ARINC 653