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Date:   Tue, 16 Jun 2020 19:07:11 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Steven Rostedt <rostedt@goodmis.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, Jun 16, 2020 at 10:59:00AM -0400, Steven Rostedt wrote:
> 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?

Either way around, who cares?

> > The right thing to do is that fair deadline server thing.
> 
> But we've been saying that for years now.

Hey, I even coded most of it, but clearly nobody cares about this enough
to finish it ...