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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200616170711.GZ2531@hirez.programming.kicks-ass.net>
Date:   Tue, 16 Jun 2020 19:07:11 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Lichao Liu <liulichao@...ngson.cn>, mingo@...hat.com,
        juri.lelli@...hat.com, vincent.guittot@...aro.org,
        dietmar.eggemann@....com, bsegall@...gle.com, mgorman@...e.de,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] sched/rt: Don't active rt throtting when no running cfs
 task

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@...radead.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@...ngson.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 ...