From: Vincent Guittot <vincent.guittot@linaro.org>
To: Juri Lelli <juri.lelli@gmail.com>
Cc: Quentin Perret <quentin.perret@arm.com>,
Ingo Molnar <mingo@kernel.org>,
Thara Gopinath <thara.gopinath@linaro.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Zhang Rui <rui.zhang@intel.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Amit Kachhap <amit.kachhap@gmail.com>,
viresh kumar <viresh.kumar@linaro.org>,
Javi Merino <javi.merino@kernel.org>,
Eduardo Valentin <edubezval@gmail.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
"open list:THERMAL" <linux-pm@vger.kernel.org>,
Ionela Voinescu <ionela.voinescu@arm.com>
Subject: Re: [RFC PATCH 0/7] Introduce thermal pressure
Date: Wed, 10 Oct 2018 15:38:57 +0200 [thread overview]
Message-ID: <CAKfTPtAyhXtKH3XeQHUHZLK+uvdsAzh5H=X+1OOAWFpP9o-L5w@mail.gmail.com> (raw)
In-Reply-To: <20181010133443.GR9130@localhost.localdomain>
On Wed, 10 Oct 2018 at 15:35, Juri Lelli <juri.lelli@gmail.com> wrote:
>
> On 10/10/18 15:08, Vincent Guittot wrote:
> > On Wed, 10 Oct 2018 at 14:50, Juri Lelli <juri.lelli@gmail.com> wrote:
> > >
> > > On 10/10/18 14:34, Vincent Guittot wrote:
> > > > Hi Juri,
> > > >
> > > > On Wed, 10 Oct 2018 at 14:23, Juri Lelli <juri.lelli@gmail.com> wrote:
> > > > >
> > > > > On 10/10/18 14:04, Vincent Guittot wrote:
> > > > >
> > > > > [...]
> > > > >
> > > > > > The problem was the same with RT, the cfs utilization was lower than
> > > > > > reality because RT steals soem cycle to CFS
> > > > > > So schedutil was selecting a lower frequency when cfs was running
> > > > > > whereas the CPU was fully used.
> > > > > > The same can happen with thermal:
> > > > > > cap the max freq because of thermal
> > > > > > the utilization with decrease.
> > > > > > remove the cap
> > > > > > the utilization is still low and you will select a low OPP because you
> > > > > > don't take into account cycle stolen by thermal like with RT
> > > > >
> > > > > What if we scale frequency component considering the capped temporary
> > > > > max?
> > > >
> > > > Do you mean using a kind of scale_thermal_capacity in accumulate_sum
> > > > when computing utilization ?
> > >
> > > Yeah, something like that I guess. So that we account for temporary
> > > "fake" 1024..
> >
> > But the utilization will not be invariant anymore across the system
>
> Mmm, I guess I might be wrong, but I was thinking we should be able to
> deal with this similarly to what we do with cpus with different max
> capacities. So, another factor? Because then, how do we handle other
> ways in which max freq can be restricted (e.g. from userspace as Javi
> was also mentioning)?
IMHO, userspace capping is a different story because it is not
expected to happen so often but it should stay for a while and in this
case, a solution is probably to rebuild the sched_domain and update
all the cpu_capacity struct and fields
next prev parent reply other threads:[~2018-10-10 13:39 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20181009162509epcas1p4fdd2e23039caa24586a4a52c6d2e7336@epcas1p4.samsung.com>
2018-10-09 16:24 ` [RFC PATCH 0/7] Introduce thermal pressure Thara Gopinath
2018-10-09 16:24 ` [RFC PATCH 1/7] sched/pelt.c: Add option to make load and util calculations frequency invariant Thara Gopinath
2018-10-09 16:24 ` [RFC PATCH 2/7] sched/pelt.c: Add support to track thermal pressure Thara Gopinath
2018-10-09 16:24 ` [RFC PATCH 3/7] sched: Add infrastructure to store and update instantaneous " Thara Gopinath
2018-10-09 16:24 ` [RFC PATCH 4/7] sched: Initialize per cpu thermal pressure structure Thara Gopinath
2018-10-09 16:25 ` [RFC PATCH 5/7] sched/fair: Enable CFS periodic tick to update thermal pressure Thara Gopinath
2018-12-04 15:43 ` Vincent Guittot
2018-10-09 16:25 ` [RFC PATCH 6/7] sched/fair: update cpu_capcity to reflect " Thara Gopinath
2018-10-10 5:57 ` Javi Merino
2018-10-10 14:22 ` Thara Gopinath
2018-10-09 16:25 ` [RFC PATCH 7/7] thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping Thara Gopinath
2018-10-10 5:44 ` [RFC PATCH 0/7] Introduce thermal pressure Javi Merino
2018-10-10 14:15 ` Thara Gopinath
2018-10-10 6:17 ` Ingo Molnar
2018-10-10 8:29 ` Quentin Perret
2018-10-10 8:50 ` Vincent Guittot
2018-10-10 9:55 ` Quentin Perret
2018-10-10 10:14 ` Vincent Guittot
2018-10-10 10:36 ` Quentin Perret
2018-10-10 12:04 ` Vincent Guittot
2018-10-10 12:23 ` Juri Lelli
2018-10-10 12:34 ` Vincent Guittot
2018-10-10 12:50 ` Juri Lelli
2018-10-10 13:08 ` Vincent Guittot
2018-10-10 13:34 ` Juri Lelli
2018-10-10 13:38 ` Vincent Guittot [this message]
2018-10-10 17:08 ` Thara Gopinath
2018-10-10 13:11 ` Quentin Perret
2018-10-10 13:05 ` Quentin Perret
2018-10-10 13:27 ` Vincent Guittot
2018-10-10 13:47 ` Quentin Perret
2018-10-10 15:19 ` Vincent Guittot
2018-10-10 16:15 ` Ionela Voinescu
2018-10-10 17:03 ` Thara Gopinath
2018-10-10 15:43 ` Thara Gopinath
2018-10-16 7:33 ` Ingo Molnar
2018-10-16 9:28 ` Lukasz Luba
2018-10-17 16:21 ` Thara Gopinath
2018-10-18 6:48 ` Ingo Molnar
2018-10-18 7:08 ` Rafael J. Wysocki
2018-10-18 7:50 ` Ingo Molnar
2018-10-18 8:14 ` Rafael J. Wysocki
2018-10-18 9:35 ` [PATCH 1/2] sched/cpufreq: Reorganize the cpufreq files Daniel Lezcano
2018-10-18 9:35 ` [PATCH 2/2] sched/cpufreq: Add the SPDX tags Daniel Lezcano
2018-10-18 9:42 ` [PATCH 1/2] sched/cpufreq: Reorganize the cpufreq files Rafael J. Wysocki
2018-10-18 9:54 ` Daniel Lezcano
2018-10-18 10:06 ` Rafael J. Wysocki
2018-10-18 10:13 ` Daniel Lezcano
2018-10-18 9:45 ` Daniel Lezcano
2018-10-19 5:24 ` kbuild test robot
2018-10-19 5:52 ` kbuild test robot
2018-10-18 9:44 ` [PATCH V2 " Daniel Lezcano
2018-10-18 9:44 ` [PATCH V2 2/2] sched/cpufreq: Add the SPDX tags Daniel Lezcano
2018-10-18 16:17 ` [RFC PATCH 0/7] Introduce thermal pressure Thara Gopinath
2018-10-19 8:02 ` Ingo Molnar
2018-10-19 11:29 ` Valentin Schneider
2018-10-10 15:35 ` Lukasz Luba
2018-10-10 16:54 ` Daniel Lezcano
2018-10-11 7:35 ` Lukasz Luba
2018-10-11 8:23 ` Daniel Lezcano
2018-10-12 9:37 ` Lukasz Luba
2018-10-10 17:30 ` Thara Gopinath
2018-10-11 11:10 ` Lukasz Luba
2018-10-16 17:11 ` Vincent Guittot
2018-10-17 16:24 ` Thara Gopinath
2018-10-18 8:00 ` Lukasz Luba
2018-10-18 8:12 ` Lukasz Luba
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