[LITMUS^RT] Maximum Tasks limit handled by scheduler (GSN-EDF)?

[Sanjib Das]

Hi Glenn,
Thanks a lot, it was only the parameters. And now its working smooth and
nice.

Thanks Again
Sanjib


On Wed, May 28, 2014 at 12:26 AM, Glenn Elliott <gelliott at cs.unc.edu> wrote:

>
> On May 27, 2014, at 6:05 PM, Sanjib Das <cnt.sanjib at googlemail.com> wrote:
>
> Dear All,
>
> Is there anyone can help me to calculate the maximum number of  tasks
> generated by https://github.com/LITMUS-RT/experiment-scripts which will
> not stall the CPUs or SOFT/HARD CPU lock occurrence or feather trace write
> will not be missed for example GSN-EDF scheduling algorithm.
>
> Thanks in Advance
> Sanjib
>
>
> The experiment-scripts are not good at generating schedulable task sets.
>  That is, it does not check the schedulability of the task sets it
> generates.  gen_exps.py allows you to place a cap on the number of tasks in
> a task set, but that does not guarantee schedulability, since
> schedulability is also determined by per-task utilization.  That is
> controlled by the period and utilization generation parameters.
>  Controlling all of these parameters is described in the readme:
> https://github.com/LITMUS-RT/experiment-scripts#gen_expspy  (also, when
> in doubt, just run “gen_exps.py --help”).
>
> I’d like to integrate experiment-scripts with schedcat’s schedulability
> test framework (https://github.com/brandenburg/schedcat).  This would
> allow us to test schedulability (with or without system overheads
> included).  I haven’t had the time to explore this yet (it would probably
> be at least a week’s effort to do it right).
>
> In the meantime, you’re just going to have to hack the generation scripts
> yourself.  Most of your work will be limited to gen/generator.py and
> gen/edf_generators.py.
>
> Here’s where experiment-scripts invokes schedcat’s task set generator:
> https://github.com/LITMUS-RT/experiment-scripts/blob/master/gen/generator.py#L119
>
> Observe that there are two control parameters: the maximum number of task
> (max_tasks) and max_util (maximum task set utilization).  Observe that
> experiment-scripts does not set max_util by default.  You’ll have to edit
> the call of _create_taskset() to provide a cap (the calls are in
> gen/edf_generators.py).
>
> -Glenn
>
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>
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