Question about round-robin scheduling.

Question about round-robin scheduling.

[孙世龙 sunshilong]

Hi, list

As per the Kconfig(
https://gitlab.denx.de/Xenomai/xenomai/-/blob/5714ceede70ccd39b1bf6c41a72cfa94f98e169a/kernel/cobalt/Kconfig
),
which says [emphasise mine]:
Cobalt has a built-in real-time class, which supports both
preemptive fixed-priority FIFO, and **round-robin scheduling**.
Cobalt supports  round-robin scheduling whereas
rt_task_create function only supports SCHED_FIFO and SCHED
(
https://xenomai.org/documentation/xenomai-3/html/xeno3prm/group__alchemy__task.html#ga03387550693c21d0223f739570ccd992
).

So, I wonder how to set a real-time task to use round-robin scheduling.
Or, am I missing something?

Thank you for your attention to this matter.
Sunshilong

Re: Question about round-robin scheduling.

[Jan Kiszka]

On 06.08.20 14:27, 孙世龙 sunshilong via Xenomai wrote:
> Hi, list
> 
> As per the Kconfig(
> https://gitlab.denx.de/Xenomai/xenomai/-/blob/5714ceede70ccd39b1bf6c41a72cfa94f98e169a/kernel/cobalt/Kconfig
> ),
> which says [emphasise mine]:
> Cobalt has a built-in real-time class, which supports both
> preemptive fixed-priority FIFO, and **round-robin scheduling**.
> Cobalt supports  round-robin scheduling whereas
> rt_task_create function only supports SCHED_FIFO and SCHED
> (
> https://xenomai.org/documentation/xenomai-3/html/xeno3prm/group__alchemy__task.html#ga03387550693c21d0223f739570ccd992
> ).
> 
> So, I wonder how to set a real-time task to use round-robin scheduling.
> Or, am I missing something?
> 

Look how SCHED_RR is commonly configured, nothing special in Xenomai. 
The only specialty is CONFIG_XENO_OPT_RR_QUANTUM.

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

Re: Question about round-robin scheduling.

[孙世龙 sunshilong]

Hi, Jan

Thank you for your reply.

>Look how SCHED_RR is commonly configured, nothing special in Xenomai.
>The only specialty is CONFIG_XENO_OPT_RR_QUANTUM.
As per the documentation(
https://xenomai.org/documentation/xenomai-3/html/xeno3prm/group__alchemy__task.html#ga03387550693c21d0223f739570ccd992),
what confuses me is that it only explicitly states that the
rt_task_create() function supports
SCHED_FIFO (other than supporting both SCHED_FIFO and SCHED_RR).

Then, how can I configure the scheduling policy of SCHED_RR?

Thank you for your attention to this matter.


On Thu, Aug 13, 2020 at 12:00 AM Jan Kiszka <jan.kiszka@siemens.com> wrote:
>
> On 06.08.20 14:27, 孙世龙 sunshilong via Xenomai wrote:
> > Hi, list
> >
> > As per the Kconfig(
> > https://gitlab.denx.de/Xenomai/xenomai/-/blob/5714ceede70ccd39b1bf6c41a72cfa94f98e169a/kernel/cobalt/Kconfig
> > ),
> > which says [emphasise mine]:
> > Cobalt has a built-in real-time class, which supports both
> > preemptive fixed-priority FIFO, and **round-robin scheduling**.
> > Cobalt supports  round-robin scheduling whereas
> > rt_task_create function only supports SCHED_FIFO and SCHED
> > (
> > https://xenomai.org/documentation/xenomai-3/html/xeno3prm/group__alchemy__task.html#ga03387550693c21d0223f739570ccd992
> > ).
> >
> > So, I wonder how to set a real-time task to use round-robin scheduling.
> > Or, am I missing something?
> >
>
> Look how SCHED_RR is commonly configured, nothing special in Xenomai.
> The only specialty is CONFIG_XENO_OPT_RR_QUANTUM.
>
> Jan
>
> --
> Siemens AG, Corporate Technology, CT RDA IOT SES-DE
> Corporate Competence Center Embedded Linux