Timeslice issues with preemption enabled

[Sebastian Huber]

On 10/06/2021 16:24, Gedare Bloom wrote:
>>> 5. Can anyone give some suggestions to solve the problem? thanks!
> Classic and POSIX APIs can be mixed. It is a poorly documented benefit
> of RTEMS. I think in this case, you should be able to use
> pthread_setschedparam(...) with passing policy == SCHED_RR to get the
> behavior you seek. You have to use posix priorities in the sched_param
> argument. though, or else your thread will have its priority changed.
> Pass the task_id instead of pthread_t as the first argument, and the
> rest should work itself out. Do let us know if that works or it
> doesn't work/you have more questions.

You can use these directives to convert priority values:

https://docs.rtems.org/branches/master/c-user/scheduling-concepts/directives.html#rtems-scheduler-map-priority-to-posix

In general, the timeslicing based on clock tick quantum is quite coarse. 
The internal timestamps would allow a much finer grained timeslicing. 
This could be added if someone is interested in a small project.

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