From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Qais Yousef <qais.yousef@arm.com>,
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>,
Eduardo Valentin <edubezval@gmail.com>,
Quentin Perret <qperret@google.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Amit Kachhap <amit.kachhap@gmail.com>,
Javi Merino <javi.merino@kernel.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>
Subject: Re: [Patch v4 4/6] sched/fair: update cpu_capcity to reflect thermal pressure
Date: Thu, 31 Oct 2019 17:17:03 +0100 [thread overview]
Message-ID: <e38e9c86-7433-7c4b-d9c1-38fd2458b953@arm.com> (raw)
In-Reply-To: <CAKfTPtCTYOBQ+TUYaGsEGK-UTQ=2of=1WYeeiMzak7ZhEPRxmA@mail.gmail.com>
On 31.10.19 16:48, Vincent Guittot wrote:
> On Thu, 31 Oct 2019 at 16:38, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote:
>>
>> On 31.10.19 11:53, Qais Yousef wrote:
>>> On 10/28/19 16:30, Peter Zijlstra wrote:
>>>> On Wed, Oct 23, 2019 at 01:28:40PM +0100, Qais Yousef wrote:
>>>>> On 10/22/19 16:34, Thara Gopinath wrote:
[...]
>>> To make sure I got this correctly - it's because avg_thermal.load_avg
>>> represents delta_capacity which is already a 'converted' form of load. So this
>>> makes avg_thermal.load_avg a util_avg really. Correct?
>>>
>>> If I managed to get it right somehow. It'd be nice if we can do inverse
>>> conversion on delta_capacity so that avg_thermal.{load_avg, util_avg} meaning
>>> is consistent across the board. But I don't feel strongly about it if this gets
>>> documented properly.
>>
>> So why can't we use rq->avg_thermal.util_avg here? Since capacity is
>> closer to util than to load?
>>
>> Is it because you want to use the influence of ___update_load_sum(...,
>> unsigned long load eq. per-cpu delta_capacity in your signal?
>>
>> Why not call it this way then?
>
> util_avg tracks a binary state with 2 fixed weights: running(1024) vs
> not running (0)
> In the case of thermal pressure, we want to track how much pressure is
> put on the CPU: capping to half the max frequency is not the same as
> capping only 10%
> load_avg is not boolean but you set the weight you want to apply and
> this weight reflects the amount of pressure.
I see. This is what I meant by 'load (weight) eq. per-cpu delta_capacity
(pressure)'.
>> diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
>> index 38210691c615..d3035457483f 100644
>> --- a/kernel/sched/pelt.c
>> +++ b/kernel/sched/pelt.c
>> @@ -357,9 +357,9 @@ int update_thermal_load_avg(u64 now, struct rq *rq,
>> u64 capacity)
>> {
>> if (___update_load_sum(now, &rq->avg_thermal,
>> capacity,
>> - capacity,
>> - capacity)) {
>> - ___update_load_avg(&rq->avg_thermal, 1, 1);
>> + 0,
>> + 0)) {
>> + ___update_load_avg(&rq->avg_thermal, 1, 0);
>> return 1;
>> }
So we could call it this way since we don't care about runnable_load or
util?
next prev parent reply other threads:[~2019-10-31 16:17 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-22 20:34 [Patch v4 0/6] Introduce Thermal Pressure Thara Gopinath
2019-10-22 20:34 ` [Patch v4 1/6] sched/pelt.c: Add support to track thermal pressure Thara Gopinath
2019-10-31 9:47 ` Ionela Voinescu
2019-10-22 20:34 ` [Patch v4 2/6] sched: Add infrastructure to store and update instantaneous " Thara Gopinath
2019-10-28 15:21 ` Peter Zijlstra
2019-10-30 21:37 ` Thara Gopinath
2019-11-01 12:17 ` Dietmar Eggemann
2019-11-01 20:57 ` Thara Gopinath
2019-11-04 17:29 ` Dietmar Eggemann
2019-11-04 17:34 ` Vincent Guittot
2019-11-04 17:41 ` Dietmar Eggemann
2019-11-04 17:48 ` Vincent Guittot
2019-10-22 20:34 ` [Patch v4 3/6] sched/fair: Enable CFS periodic tick to update " Thara Gopinath
2019-10-28 15:24 ` Peter Zijlstra
2019-10-28 15:27 ` Peter Zijlstra
2019-10-30 21:41 ` Thara Gopinath
2019-10-31 16:11 ` Dietmar Eggemann
2019-10-31 16:46 ` Thara Gopinath
2019-10-22 20:34 ` [Patch v4 4/6] sched/fair: update cpu_capcity to reflect " Thara Gopinath
2019-10-23 12:28 ` Qais Yousef
2019-10-28 15:30 ` Peter Zijlstra
2019-10-31 10:53 ` Qais Yousef
2019-10-31 15:38 ` Dietmar Eggemann
2019-10-31 15:48 ` Vincent Guittot
2019-10-31 16:17 ` Dietmar Eggemann [this message]
2019-10-31 16:31 ` Vincent Guittot
2019-10-31 16:44 ` Dietmar Eggemann
2019-10-31 16:03 ` Thara Gopinath
2019-10-31 16:56 ` Qais Yousef
2019-10-22 20:34 ` [Patch v4 5/6] thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping Thara Gopinath
2019-10-28 15:33 ` Peter Zijlstra
2019-10-31 16:29 ` Dietmar Eggemann
2019-10-31 16:38 ` Vincent Guittot
2019-11-01 15:47 ` Ionela Voinescu
2019-11-01 21:04 ` Thara Gopinath
2019-11-04 14:41 ` Ionela Voinescu
2019-10-31 16:46 ` Thara Gopinath
2019-10-22 20:34 ` [Patch v4 6/6] sched: thermal: Enable tuning of decay period Thara Gopinath
2019-10-28 15:42 ` Peter Zijlstra
2019-11-04 16:12 ` Ionela Voinescu
2019-11-05 20:26 ` Thara Gopinath
2019-11-05 21:29 ` Ionela Voinescu
2019-10-29 15:34 ` [Patch v4 0/6] Introduce Thermal Pressure Daniel Lezcano
2019-10-31 10:07 ` Ionela Voinescu
2019-10-31 11:54 ` Daniel Lezcano
2019-10-31 12:57 ` Ionela Voinescu
2019-10-31 17:48 ` Daniel Lezcano
2019-10-31 9:44 ` Ionela Voinescu
2019-10-31 16:41 ` Thara Gopinath
2019-10-31 16:52 ` Thara Gopinath
2019-11-05 21:04 ` Ionela Voinescu
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