About scheduling mechanism rtems task

Gedare Bloom gedare at rtems.org
Mon Nov 30 23:04:54 UTC 2015


On Mon, Nov 30, 2015 at 1:14 PM, 박시형 <inputsh at gmail.com> wrote:
> Hello?
> I'm the beginner of RTEMS and C language.
>
> I'm trying to make rtems task to running given duration(execution time) and
> period.
> I mean, I want to running like followings.
> 'task 1'  duration 10 ms and period is 10 ms.
> 'task 2'  duration 15 ms and period is 20 ms.
>
Period usually means how often the task executes, so a period of 10ms
means that task should execute every 10ms. If task 1 really takes 10ms
every 10ms, then there is no other time for task2? Or do you want the
period to be duration+10ms for  task1?

Can you define what you mean by duration and period?

You might like to read
https://docs.rtems.org/doc-current/share/rtems/html/c_user/Rate-Monotonic-Manager.html#Rate-Monotonic-Manager
if you have a real-time periodic application you need to satisfy.

> So, when I made tasks I give RTEMS_NO_PREEMPT | RTEMS_TIMESLICE for tasks
> mode.
> But in this case, I can't give each time slice to each task.
>
> Therefore I was try RTEMS timer for duration and rtems_task_wake_after for
> period.
> I think timer triggered and timer handler called rtems_task_wake_after
> function then I can solve that problem. But it wasn't work.
>
Maybe you can post your code. I don't entirely understand what you are
trying to accomplish. You can 'grep' or search through the
rtems.git/testsuites for lots of examples of using the various rtems_
functions.

I don't think there is any function that would let you say "execute
for x amount of time" if that is what you mean by duration.

Gedare

> How can i fix this thing.. Which method can i use for duration and period.
> regards.
>
>
>
>
>
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