From: Juri Lelli <juri.lelli@arm.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Vikram Mulukutla <markivx@codeaurora.org>,
Mark Brown <broonie@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
mingo@redhat.com, viresh.kumar@linaro.org,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
tglx@linutronix.de, vincent.guittot@linaro.org,
rostedt@goodmis.org, luca.abeni@santannapisa.it,
claudio@evidence.eu.com, tommaso.cucinotta@santannapisa.it,
bristot@redhat.com, mathieu.poirier@linaro.org,
tkjos@android.com, joelaf@google.com, andresoportus@google.com,
morten.rasmussen@arm.com, dietmar.eggemann@arm.com,
patrick.bellasi@arm.com, Ingo Molnar <mingo@kernel.org>,
linux-kernel-owner@vger.kernel.org
Subject: Re: [RFD PATCH 3/5] sched/cpufreq_schedutil: make worker kthread be SCHED_DEADLINE
Date: Fri, 31 Mar 2017 08:26:52 +0100 [thread overview]
Message-ID: <20170331072652.GJ19929@e106622-lin> (raw)
In-Reply-To: <2683548.WpoELJxfrb@aspire.rjw.lan>
On 30/03/17 22:22, Rafael J. Wysocki wrote:
> On Thursday, March 30, 2017 08:50:11 AM Vikram Mulukutla wrote:
> >
> > > OK
> > >
> > > So there are two pieces here.
> > >
> > > One is that if we want *all* drivers to work with schedutil, we need to
> > > keep
> > > the kthread for the ones that will never be reworked (because nobody
> > > cares
> > > etc). But then perhaps the kthread implementation may be left alone
> > > (because
> > > nobody cares etc).
> > >
> > > The second one is that there are drivers operating in-context that work
> > > with
> > > schedutil already, so I don't see major obstacles to making more
> > > drivers work
> > > that way. That would be only a matter of reworking the drivers in
> > > question.
> > >
> > > Thanks,
> > > Rafael
> >
> > There are some MSM platforms that do need a kthread and would love to
> > use
> > schedutil. This is all mainly due to the point that Vincent raised;
> > having
> > to actually wait for voltage transitions before clock switches. I can't
> > speak about the future, but that's the situation right now. Leaving the
> > kthread alone for now would be appreciated!
>
> I was not arguing for removing the kthread (quite opposite rather).
>
> My point was that *if* it is viable to rework drivers to operate in-context,
> that would be the way to go IMO instead of messing up with the kthread thing.
>
Right, I agree. Problem is that in principle we might still want to use
DEADLINE with the other platforms (MSM being a perfect example), so IMHO
we should still try to find a solution for the kthread anyway.
next prev parent reply other threads:[~2017-03-31 7:27 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-24 14:08 [RFD PATCH 0/5] SCHED_DEADLINE freq/cpu invariance and OPP selection Juri Lelli
2017-03-24 14:08 ` [RFD PATCH 1/5] sched/cpufreq_schedutil: make use of DEADLINE utilization signal Juri Lelli
2017-03-24 14:08 ` [RFD PATCH 2/5] sched/deadline: move cpu frequency selection triggering points Juri Lelli
2017-03-24 14:08 ` [RFD PATCH 3/5] sched/cpufreq_schedutil: make worker kthread be SCHED_DEADLINE Juri Lelli
2017-03-27 16:50 ` Peter Zijlstra
2017-03-27 17:01 ` Juri Lelli
2017-03-27 17:05 ` Rafael J. Wysocki
2017-03-27 17:13 ` Juri Lelli
2017-03-27 17:37 ` Rafael J. Wysocki
2017-03-27 18:09 ` Mark Brown
2017-03-30 15:50 ` Vikram Mulukutla
2017-03-30 20:22 ` Rafael J. Wysocki
2017-03-31 7:26 ` Juri Lelli [this message]
2017-03-27 18:05 ` Mark Brown
2017-03-28 9:29 ` Vincent Guittot
2017-03-28 10:20 ` Peter Zijlstra
2017-03-24 14:08 ` [RFD PATCH 4/5] sched/cpufreq_schedutil: always consider all CPUs when deciding next freq Juri Lelli
2017-03-29 22:41 ` Rafael J. Wysocki
2017-03-30 8:58 ` Juri Lelli
2017-03-30 13:21 ` Vincent Guittot
2017-03-30 20:13 ` Rafael J. Wysocki
2017-03-31 7:31 ` Juri Lelli
2017-03-31 9:03 ` Rafael J. Wysocki
2017-03-31 9:16 ` Juri Lelli
2017-03-24 14:09 ` [RFD PATCH 5/5] sched/deadline: make bandwidth enforcement scale-invariant Juri Lelli
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