Re: report a bug about sched_rt

Arjan van de Ven
2009-07-25T17:55:09Z

On Fri, 24 Jul 2009 18:57:35 +0800
sen wang <wangsen.linux@gmail.com> wrote:

> I find something is wrong about sched_rt.
>
> when I am debugging my system with rt_bandwidth_enabled, there is a
> running realtime FIFO task in the sched_rt running queue and
> the fair running queue is empty. I found the idle task will be
> scheduled up when the running task still lie in the sched_rt running
> queue!
>
> this will happen when rt runqueue passed it's rt_bandwidth_enabled
> runtime,then the scheduler choose the idle task instead of realtime
> FIFO task.
>
> the reason lie in: when scheduler try to pick up a realtime FIFO task,
> it will check if rt_throttled is enabled,
> if so, it'll return and try fair queue but it is empty, then it come
> to the sched_idle class.
>
> I don't think it reasonable, we should give the realtime FIFO task the
> chance, even when rt runqueue passed it's runtime.
> because it is cpu's free time.

sounds like a good power limiting feature...

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Arjan van de Ven Intel Open Source Technology Centre
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