Re: [PATCH] sched/rt: Don't active rt throtting when no running cfs task

[Steven Rostedt]

On Tue, 16 Jun 2020 16:01:58 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Tue, Jun 16, 2020 at 09:50:27AM -0400, Steven Rostedt wrote:
> > On Tue, 16 Jun 2020 20:37:29 +0800
> > Lichao Liu <liulichao@xxxxxxxxxxx> wrote:
> >   
> > > Active rt throtting will dequeue rt_rq from rq at least 50ms,
> > > When there is no running cfs task, do we still active it?
> > >   
> > 
> > This is something I would like to have.
> > 
> > Peter, what's your thought on this?  
> 
> I'd love to just delete all of this.. that said, I'm not sure this
> change makes sense, because it doesn't deal sanely with the case where
> the task will appear right after we did this.

I haven't looked closely at the surrounding code, but wouldn't it get
throttled in the next period? Do we care if a task has to wait a bit
longer?

> 
> The right thing to do is that fair deadline server thing.

But we've been saying that for years now.

-- Steve