[LITMUS^RT] Experiment Script

[Glenn Elliott]

On Apr 22, 2014, at 8:15 AM, Sanjib Das <cnt.sanjib at googlemail.com> wrote:

> Dear Everyone,
> 
> I am using the experiment script from the following link https://github.com/LITMUS-RT/experiment-scripts to generate the synthetic tasks and was able to simulate for PSN-EDF. 
> 
> Can anyone help me how can I generate a reasonable about of taskset for simulation using PFAIR scheduling algorithm(Implementation of the PD^2 pfair scheduling algorithm. This implementation realizes "early releasing), provided in LIRMUS-RT version 2013.1.
> 
> I would be glade with any information that leads me to simulate the mentioned algorithm above.
> 
> Regards
> Sanjib


Hi Sanjib,

In response to your other email on the availability of PFAIR, it’s in the latest Litmus kernel (code: https://github.com/LITMUS-RT/litmus-rt/blob/master/litmus/sched_pfair.c).  Just make sure that you properly configure the kernel at compile-time to get it.  As you might see in litmus/Kconfig (https://github.com/LITMUS-RT/litmus-rt/blob/master/litmus/Kconfig#L15), CONFIG_HIGH_RES_TIMERS and CONFIG_HZ_PERIODIC must be set and CONFIG_HZ must == 1000.

Regarding the experiment-scripts, currently there are no task-set generators for pfair.  I believe you could quickly copy and modify the C-EDF generator to create task sets for pfair (this is because the pfair plugin can be clustered along cache-level boundaries, just like C-EDF).

My suggestion:
Step 1: Replicate the CedfGenerator (https://github.com/LITMUS-RT/experiment-scripts/blob/master/gen/edf_generators.py#75), naming it CpfairGenerator or some such, and make the appropriate changes to make it use pfair.
Step 2: Add your new generator to gen/__init__.py (https://github.com/LITMUS-RT/experiment-scripts/blob/master/gen/__init__.py)
Step 3: I think that’s it.  You should be able to follow the tutorial for gen_exps.py here: https://github.com/LITMUS-RT/experiment-scripts

These changes should take more than 30 minutes to add and test (assuming that I haven’t missed anything).  I’d be happy to accept a patch that adds pfair functionality.

-Glenn
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