[LITMUS^RT] CPU usage of real-time tasks

[Youcef Amine Benabbas]

Hi Jonathan,

Thank you for your reply. I am already doing what you described in your
reply for my work.

The point is, suppose the /usr/bin/time is executed as a real-time task
under litmus; would the results it provides be suitable for evaluation
purposes, from a real-time point of view?

Regards,
Youcef 

On Sun, 2013-03-31 at 11:56 -0400, Jonathan Herman wrote:
> Hi Youcef,
> 
> 
> The best way to do this would be to use the sched_trace
> infrastructure. The process of capturing this data while a task is
> running is described here:
> https://wiki.litmus-rt.org/litmus/Tracing
> 
> 
> You would have you write your own code to parse this data and output
> task utilization. The unit-trace repository contains python code which
> you can use as a guide:
> http://cs.unc.edu/~mollison/unit-trace/
> 
> 
> The file which parses the sched_trace data is
> unit-trace/unit_trace/trace_reader.py. Sorry for not noticing your
> email sooner.
> 
> On Sun, Mar 24, 2013 at 11:55 AM, Youcef Amine Benabbas
> <s9yobena at stud.uni-saarland.de> wrote:
>         Hi everyone,
>         
>         Is there a way to precisely know the cpu usage of a real-time
>         task. For
>         instance, rtspin (from liblitmus) receives as arguments a wcet
>         and
>         period; however the utilization of an rtspin task measured by
>         the "time"
>         command is different from wcet/period.
>         
>         Since the time command will not run in the presence of
>         real-time tasks,
>         I would like to know if there exists an alternative to
>         precisely know
>         the cpu utilization of a real-time task (this may be needed if
>         the
>         performance of a real-time scheduling algorithm  has to be
>         conducted
>         based on the total utilization of a given task-set).
>         
>         Kind regards,
>         Youcef
>         
>         
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> 
> 
> 
> 
> -- 
> Jonathan Herman
> Department of Computer Science at UNC Chapel Hill
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