* ANN : New release of Cheddar, a real time scheduling simulator
@ 2003-09-04 13:28 Frank Singhoff
0 siblings, 0 replies; 2+ messages in thread
From: Frank Singhoff @ 2003-09-04 13:28 UTC (permalink / raw)
The EA 2215 team is pleased to announce a new release of Cheddar,
a free real time scheduling simulator.
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 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 and buffers.
The framework includes feasibility tests and simulation tools. Feasibility tests
can be applied to check that task response times are met and that buffer size are bounded.
When feasibility tests can not be applied, the studied application can be analysed
with scheduling and buffer simulations.
The current release is now 1.3p1.
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
Cheddar is written in Ada with GtkAda. It runs on Solaris, Linux and
win32 boxes and should run on every GNAT/GtkAda supported platforms
(see ACT web site for details).
1) With Cheddar, you can :
-------------------------
- Do scheduling simulations with classical real time schedulers
(Rate Monotonic, Deadline Monotonic,
Least Laxity First, Earliest Deadline
First, POSIX.4 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 or buffers (without scheduling simulation) :
- Compute task response times.
- Apply processor utilization test.
- Schedule for a given base period.
- Compute bound on buffer size (when buffer 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.
- Do simulation when tasks are randomly activated.
2) The most important new features are :
----------------------------------------
- Cheddar project files are now saved in a XML
format. Project can then be shared
between several plate-formes and tools
- Add response time feasibility tests for RM/DM/POSIX.4 in the
non preemptive case. Add EDF/LLF response time feasibility tests
in the preemptive and the non preemptive case
- Add response time from scheduling simulation
- When Cheddar crashes, the ongoing project is saved
in a XML file called "cheddar_bug.xml"
and then, project editing is not loosed any more
- Add parametric schedulers
- Produce simulation results in string or XML format
- Add some classic Queueing results in the
framework to help buffer analysis
- Add a C inferface to the Ada framework
- Add some tools to do random scheduling simulation
- Fix some bugs (see BUGS file)
3) Work in progress :
----------------------
During the next year, we plan to improve the tool with the following features :
- Update the user's guide.
- Improvement of the buffer analysis features.
- Add feasibility tests and simulation features for multi-processors
systems
- Rebuild of shared resources support : adding new protocols and
add parametric shared resource protocols.
Feel free to contact us for help or bugs report.
Best Regards,
The EA 2215 team
^ permalink raw reply [flat|nested] 2+ messages in thread
* ANN : New release of Cheddar : a real time scheduling simulator
@ 2004-09-08 15:05 Frank Singhoff
0 siblings, 0 replies; 2+ messages in thread
From: Frank Singhoff @ 2004-09-08 15:05 UTC (permalink / raw)
ANN : New release of Cheddar, a free real time scheduling simulator
The EA 2215 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 EA 2215 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 1.3p3.
If you are a regular Cheddar's user, we strongly advice you to switch
to the 1.3p3 release due to the large amount of 1.3p2 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 1.3p3 :
----------------------------------------------------------
- Fix many bugs of the previous release (see BUGS file)
- Add a new user interface of the scheduling simulation service.
With 1.3p3, Cheddar provides two different scheduling simulations :
customized or uncustomized scheduling.
Uncustomized simulation draws time line
and computes worst case response time
from simulation. This service is called
from the "Scheduling Simulation" pixmap.
Customized simulation draws time line
and can compute many others measures
(eg. Worst/Best/Average cases
of shared resource blocking and response time
time from simulation).
This service is called from the menu
"Tools/Scheduling/Scheduling simulation" (F. Singhoff)
- Add a way to display or export event tables
produced by the scheduling simulator engine. Event
tables are XML formated. An event table
is a set of data which stores a computed
scheduling. (F. Singhoff)
- Add a way to import event tables computed by
other tools. This service allows you
to run analysis on scheduling produced by
operating system, object request broker or
any applications. (F. Singhoff).
- Add Partitioning tools for multiprocessor
systems scheduled with Rate Monotonic.
Several partitioning strategies are
provided (RM Best Fit, RM Next Fit, RM
First Fit, RMGT and RMST)
(M. Nivala)
- Fix errors on utilization factor feasibility tests.
In the previous release, preemptive EDF and RM
tests were applied by error on other schedulers.
(H. Martin, S. Bothorel)
- Add user-defined event analyzers. User-defined
analyzer can be run on a given scheduling to look
for user specific properties.
User-defined event analyzers
are pieces of user code which scan and do analysis
on event tables.
(F. Singhoff)
- Add user-defined task arrival pattern. This
feature should allow us to easily define new
task activation patterns (ex : bursty task activation;
jitter constraint activation, sporadic
activation,...)
(H. Huopana, F. Singhoff)
- Add a simple message scheduling.
Actually, message scheduling is limited with
constant communication delay messages and with
sending tasks which send messages at the start
of their activation. This service have to be
extended in the next release to be really usefull.
(G. Oliva, F. Charlet)
- Add a sub-program To detect priority inversion
from scheduling simulation (F. Singhoff)
- Add a C interface to call the framework
from C programs.
(F. Singhoff)
- Shared resource states are displayed on
the time line.
(E. Vilain)
3) Work in progress :
----------------------
During the next year, we plan to improve the tool with the following
features :
- Update the user's guide according to the new 1.3p3 features
- Improvement of the buffer analysis features with queueing
theory analysis tools.
- Provide a way to import/export application specifications
in AADL.
- Improvement of message scheduling with :
- 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)
- Fixing a buggy service which should detects deadlock from simulation.
- Completing available services on event tables.
--------------------------------------------------------
Feel free to contact us for help or bugs report.
Best Regards,
The EA 2215 team
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