Ann. : new release of Cheddar, a free real time scheduling analyzer

Ann. : new release of Cheddar, a free real time scheduling analyzer

[Singhoff]

The LYSIC team is pleased to announce a new release of Cheddar.

Cheddar is a free real time scheduling tool. Cheddar is designed for
checking task temporal constraints and buffer sizes 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 purposes.

Cheddar is developed and maintened by the LYSIC Team,
University of Brest.


Cheddar is composed of two independent parts : an editor used to
describe a real time application/system, and a framework.
The editor allows you to describe systems composed of several processors
which own
tasks, shared resources, buffers and which exchange messages.
The framework includes many feasibility tests and simulation tools.
 Feasibility tests
can be applied to check that task response times are met and that buffers
have bounded size.
When feasibility tests can not be applied, the studied application can be
analyzed
 with scheduling and buffer simulations.
Cheddar provides a way to quickly define "user-defined schedulers" to
model scheduling of ad-hoc applications/systems (ex : ARINC 653).

Cheddar is written in Ada. The  graphical editor is made with GtkAda.
Cheddar runs on Solaris, Linux and
win32 boxes and should run on every GNAT/GtkAda supported platforms


The current release is now 1.3p5.
If you are a regular Cheddar's user, we strongly advice you to switch
to the 1.3p5 release due to the large amount of 1.3p3 bugs 
that we fixed.


Cheddar is distributed under the GNU GPL license.
It's a free software, and you are welcome to  redistribute it under
certain conditions;
See the GNU General Public License for  details.
Source code, binaries and documentations can be freely downloaded from
http://beru.univ-brest.fr/~singhoff/cheddar


1) Summary of features :
------------------------


- Do scheduling simulations with classical real time schedulers
	(Rate Monotonic, Deadline Monotonic,
	Least Laxity First, Earliest Deadline
	First, POSIX queueing policies : SCHED_OTHERS,
	SCHED_FIFO and SCHED_RR) with
	different type of tasks (aperiodic, periodic, task
	activated with a poisson process law, ...)
- Extract information from scheduling simulation.
	(buffer utilization factor, task response times, task missed deadlines,
	number of preemption, ...)
- Apply feasibility tests on tasks and buffers (without scheduling
	simulation) :
        - Compute task response time bounds.
        - Apply processor utilization tests.
	- Compute bound on buffer size (when buffers are shared by periodic tasks)
- Shared resources support (scheduling and
	blocking time analysis).  Supported protocols : PIP, PCP.
- Tools to express and do simulations/feasibility tests with task
	precedencies :
	- Schedule tasks according to task precedencies
	- Compute Tindell end to end response time.
	- Apply Chetto and Blazewicz algorithms.
- Tools to run scheduling simulation in the case of 
	multiprocessors systems
- Do simulation when tasks are randomly activated.
- Can run scheduling simulation on user-defined scheduler
	and task arrival patterns.
- Run user-defined analysis on scheduling simulation.
- ...



2) Most of new features provided by 1.3p5 :
-------------------------------------------


      - Fix many bugs of the previous release (see BUGS file)

      - Add AADL import and export.
	This feature is based on
        the Ocarina AADL parser distributed by the ENST 
		(F. Singhoff)
      - Perform several optimization in order to
        increase global performance.
        (ex : decrease memory footprint)
      - Add round robin and time sharing
        built-in schedulers (F. Singhoff)
      - Add FreeBsd Makefile.vars (C.P. Gloster)
      - Feasibility tests can be called by users 
        processor by processor and feasibility
        test by feasibility test.
        (see customized feasibility tests)
		(F. Singhoff)
      - Refactoring of some basic widgets
		(H. Lapinoja, F. Singhoff)
      - Improve text displayed in the main root window
        when response time and
    	  feasibility tests are performed on a project
		(F. Singhoff)
      - Extend the data model of cheddar to include 
	  the abstraction of address spaces
		(F. Singhoff)
      - Some parametric variable can be set into the 
	  parametric code (F. Singhoff)
      - Provide extended buffer analysis tools :
	  simulation and feasibility tests
	  in cases of periodic and randomly
	  activated tasks
		(J. Legrand, F. Singhoff)
      - Users can tune which events the simulator 
        engine will generate at simulation time
        (see Tools/Scheduling/Options)
        Warning : "task_activation" and "running_task"
	  can not be ungenerated since they are
	  needed by many analysis tools
             	(F. Singhoff)



Thanks to H. Lapinoja, J. Legrand, 
T. Vergnaud, T. Ren, K. Bryan,  C.P. Gloster,
J. Stemerdink and  F. R. De la Rocha
for their help on this new release (tests, bug reports or
new features)


3) Work in progress  :
----------------------


For the next year, we plan to improve the tool with the following
features :


- Provide a global memory analysis (task stack, text/data segments ...)
- Add Hierarchical schedulers support.
- Updated the graphical editor in order to take into 
      account GtkAda 2.2
- Update the user's guide according to the new provided features
- Improvement of message scheduling with :
	- End to end response time with message scheduling.
	- Allowing message sending at any time of a task
		capacity
	- Providing a way to user-defined message
		delay communication by specification
		of user-defined message scheduling 
			(as user-defined scheduler)	
- Fix a buggy service which should detect deadlock from simulation.


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Feel free to contact us for help or bugs report.



Best Regards,
The LYSIC team