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Date:   Tue, 16 Jun 2020 10:59:00 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Lichao Liu <liulichao@loongson.cn>, mingo@redhat.com,
        juri.lelli@redhat.com, vincent.guittot@linaro.org,
        dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched/rt: Don't active rt throtting when no running cfs
 task
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On Tue, 16 Jun 2020 16:01:58 +0200
Peter Zijlstra <peterz@infradead.org> 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@loongson.cn> 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