From: Vincent Guittot <vincent.guittot@linaro.org>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Thara Gopinath <thara.gopinath@linaro.org>,
Ingo Molnar <mingo@redhat.com>,
Ionela Voinescu <ionela.voinescu@arm.com>,
Zhang Rui <rui.zhang@intel.com>,
Quentin Perret <qperret@google.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
viresh kumar <viresh.kumar@linaro.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Amit Kachhap <amit.kachhap@gmail.com>,
Javi Merino <javi.merino@kernel.org>,
Amit Kucheria <amit.kucheria@verdurent.com>
Subject: Re: [Patch v8 4/7] sched/fair: Enable periodic update of average thermal pressure
Date: Thu, 30 Jan 2020 10:49:20 +0100 [thread overview]
Message-ID: <CAKfTPtBzoLnvAJ7sjPogMYS=WwBbdzWO07Kj=KDFVpO4=Su5ow@mail.gmail.com> (raw)
In-Reply-To: <f5d64110-85bf-92a5-9d63-faa5d64d2155@arm.com>
On Wed, 29 Jan 2020 at 16:41, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote:
>
> On 27/01/2020 16:15, Vincent Guittot wrote:
> > On Mon, 27 Jan 2020 at 13:09, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote:
> >>
> >> On 24/01/2020 16:45, Vincent Guittot wrote:
> >>> On Fri, 24 Jan 2020 at 16:37, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote:
> >>>>
> >>>> On 17/01/2020 16:39, Vincent Guittot wrote:
> >>>>> On Fri, 17 Jan 2020 at 15:55, Peter Zijlstra <peterz@infradead.org> wrote:
> >>>>>>
> >>>>>> On Fri, Jan 17, 2020 at 02:22:51PM +0100, Vincent Guittot wrote:
> >>>>>>> On Thu, 16 Jan 2020 at 16:15, Peter Zijlstra <peterz@infradead.org> wrote:
> >>
> >> [...]
> >>
> >>>> The 'now' argument is one thing but why not:
> >>>>
> >>>> -int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
> >>>> +int update_thermal_load_avg(u64 now, struct rq *rq)
> >>>> {
> >>>> + u64 capacity = arch_cpu_thermal_pressure(cpu_of(rq));
> >>>> +
> >>>> if (___update_load_sum(now, &rq->avg_thermal,
> >>>>
> >>>> This would make the call-sites __update_blocked_others() and
> >>>> task_tick(_fair)() cleaner.
> >>>
> >>> I prefer to keep the capacity as argument. This is more aligned with
> >>> others that provides the value of the signal to apply
> >>>
> >>>>
> >>>> I guess the argument is not to pollute pelt.c. But it already contains
> >>>
> >>> you've got it. I don't want to pollute the pelt.c file with things not
> >>> related to pelt but thermal as an example.
> >>>
> >>>> arch_scale_[freq|cpu]_capacity() for irq.
> >>
> >> But isn't arch_cpu_thermal_pressure() not exactly the same as
> >> arch_scale_cpu_capacity() and arch_scale_freq_capacity()?
> >>
> >> All of them are defined by default within the scheduler code
> >> [include/linux/sched/topology.h or kernel/sched/sched.h] and can be
> >> overwritten by arch code with a fast implementation (e.g. returning a
> >> per-cpu variable).
> >>
> >> So why is using arch_scale_freq_capacity() and arch_scale_cpu_capacity()
> >> in update_irq_load_avg [kernel/sched/pelt.c] and update_rq_clock_pelt()
> >
> > As explained previously, update_irq_load_avg is an exception and not
> > the example to follow. update_rt/dl_rq_load_avg are the example to
> > follow and fixing update_irq_load_avg exception is on my todo list
>
> There is already a v9 but I comment here so the thread stays intact.
>
> I guess this thread leads to nowhere. For me the question is do we
> review against existing code or some possible future changes? The
> arguments didn't convince me so far.
> But we're not talking functional issues here so I won't continue to push
> for change on this one here.
>
> >> [kernel/sched/pelt.h] OK but arch_cpu_thermal_pressure() in
> >> update_thermal_load_avg() [kernel/sched/pelt.c] not?
> >>
> >> Shouldn't arch_cpu_thermal_pressure() not be called
> >> arch_scale_thermal_capacity() to highlight the fact that those three
> >
> > Quoted from cover letter https://lkml.org/lkml/2020/1/14/1164:
> > "
> > v6->v7:
> > - ...
> > - Renamed arch_scale_thermal_capacity to arch_cpu_thermal_pressure
> > as per review comments from Peter, Dietmar and Ionela.
> > -...
> >
> > "
>
> I went back to the v6 review. Peter originally asked for a better name
> (or an additional comment) for arch_scale_thermal_capacity() because the
> return value is not capacity.
>
> So IMHO arch_scale_thermal_pressure() is a good name for keeping this
> aligned w/ the other arch_scale_* functions and to address this review
> comment.
>
> arch_scale_cpu_capacity() - scale capacity by cpu
> arch_scale_freq_capacity() - scale capacity by frequency
> arch_scale_thermal_pressure() - scale pressure (1 - capacity) by thermal
If arch_scale_thermal_pressure() is ok for everybody i'm fine too.
I don't have a strong opinion about the name of the function as long
as we don't go back and forth
>
> [...]
next prev parent reply other threads:[~2020-01-30 9:49 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 19:57 [Patch v8 0/7] Introduce Thermal Pressure Thara Gopinath
2020-01-14 19:57 ` [Patch v8 1/7] sched/pelt: Add support to track thermal pressure Thara Gopinath
2020-01-16 15:17 ` Peter Zijlstra
2020-01-23 19:15 ` Dietmar Eggemann
2020-01-24 19:07 ` Thara Gopinath
2020-01-27 9:28 ` Dietmar Eggemann
2020-01-28 13:32 ` Thara Gopinath
2020-01-28 16:15 ` Dietmar Eggemann
2020-02-13 12:03 ` Amit Kucheria
2020-02-13 12:31 ` Amit Kucheria
2020-01-14 19:57 ` [Patch v8 2/7] sched/topology: Add hook to read per cpu " Thara Gopinath
2020-01-14 19:57 ` [Patch v8 3/7] arm,arm64,drivers:Add infrastructure to store and update instantaneous " Thara Gopinath
2020-01-14 19:57 ` [Patch v8 4/7] sched/fair: Enable periodic update of average " Thara Gopinath
2020-01-16 15:15 ` Peter Zijlstra
2020-01-17 11:40 ` Quentin Perret
2020-01-17 12:31 ` Peter Zijlstra
2020-01-17 13:17 ` Vincent Guittot
2020-01-17 13:45 ` Quentin Perret
2020-01-17 13:22 ` Vincent Guittot
2020-01-17 14:55 ` Peter Zijlstra
2020-01-17 15:39 ` Vincent Guittot
2020-01-24 15:37 ` Dietmar Eggemann
2020-01-24 15:45 ` Vincent Guittot
2020-01-27 12:09 ` Dietmar Eggemann
2020-01-27 15:15 ` Vincent Guittot
2020-01-29 15:41 ` Dietmar Eggemann
2020-01-30 9:49 ` Vincent Guittot [this message]
2020-01-17 20:20 ` Thara Gopinath
2020-01-14 19:57 ` [Patch v8 5/7] sched/fair: update cpu_capacity to reflect " Thara Gopinath
2020-01-14 19:57 ` [Patch v8 6/7] thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping Thara Gopinath
2020-01-14 19:57 ` [Patch v8 7/7] sched/fair: Enable tuning of decay period Thara Gopinath
2020-01-17 11:47 ` Quentin Perret
2020-01-17 15:45 ` Thara Gopinath
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