Cheddar is a free real time scheduling framework. Cheddar is designed for checking task temporal constraints of a real time application/system. It can also help you for quick prototyping of real time schedulers. Finally, it can be used for educational purpose. Cheddar is a free software, and you are welcome to redistribute it under certain conditions; See the GNU General Public License for details. The Cheddar project was started in 2002 by Frank Singhoff, Lab-STICC Team, University of Brest. Since 2008, Ellidiss technologies also contributes to the development of Cheddar and provides industrial support.

WARNING : this user's guide supposes that you have a minimum background on real-time scheduling. If it's not your case, take a look on this link which includes some very basic articles or book references. This link also provides a description of the analytical methods implemented into Cheddar and gives some publications that show how to use Cheddar.

To completed this user guide, you also have in this technical report , a precise description of all entities used in Cheddar.

• I. Basic scheduling simulation features and feasibility tests
• I.1 First step : a simple scheduling simulation
• I.2 Other available schedulers and task arrival patterns
• I.3 Scheduling options
• II. About Cheddar project files (XML and AADL files)
• III. Summary of the Cheddar command line
• IV. Scheduling with dependencies
• IV.1 Shared resources analysis tools
• IV.2 Task precedencies
• IV.2.1 Editing Task precedencies
• IV.2.2 How to transform a dependent task set into an independent task set : the Chetto/Blazewicz modification rules
• IV.2.3 Computing end to end response time : the Holistic approach
• IV.3 Buffer analysis tools
• IV.4 Message scheduling services
• V. Multiprocessor scheduling services
• V.1 Global multiprocessor scheduling
• V.2 Cache interference analysis
• V.3 Memory interferences analysis
• V.4 Network-On-Chip interferences analysis
• V.5 Partitionning algorithms
• VI. User-defined simulation code : how to run simulations of specific systems
• VI.1 Examples of user-defined schedulers
• VI.1.1 Low-level statements versus High-level statements
• VI.1.2 User-defined scheduler built with User's defined Task Parameters
• VI.2 Scheduling with user-defined task arrival patterns
• VI.3 Running a simulation with a user-defined scheduler
• VI.4 Looking for user-defined properties during a scheduling simulation
• VI.5 List of predefined variables and available statements for user-defined code
• VII. Using Cheddar within OSATE 2
• VII.1 How to install Cheddar plugin within OSATE 2
• VII.2 Cheddar plugins simple example of use
• VII.3 Cheddar AADL properties
• VIII. Hierarchical scheduling
• VIII.1 ARINC 653 scheduling
• VIII.1.1 How to model an ARINC 653 two-levels scheduling
• VIII.1.2 Example of an ARINC 653 scheduling
• VIII.2 Aperiodic server hierarchical scheduling
• VIX. MILS and security services
• X. Summary of Cheddar's editor menus and sub-menus