From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Matthias Kaehlcke <mka@chromium.org>,
Doug Anderson <dianders@chromium.org>
Cc: Lukasz Luba <lukasz.luba@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux PM <linux-pm@vger.kernel.org>,
amit daniel kachhap <amit.kachhap@gmail.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Amit Kucheria <amitk@kernel.org>, Zhang Rui <rui.zhang@intel.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Pierre.Gondois@arm.com, Stephen Boyd <swboyd@chromium.org>,
Rajendra Nayak <rnayak@codeaurora.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>
Subject: Re: [PATCH 1/2] thermal: cooling: Check Energy Model type in cpufreq_cooling and devfreq_cooling
Date: Thu, 17 Feb 2022 10:59:12 +0100 [thread overview]
Message-ID: <bfd33bfe-025e-bfba-04f2-e3c39822d68e@linaro.org> (raw)
In-Reply-To: <Yg13JoHLmeFGPOAW@google.com>
On 16/02/2022 23:13, Matthias Kaehlcke wrote:
> On Wed, Feb 16, 2022 at 09:33:50AM -0800, Doug Anderson wrote:
>> Hi,
>>
>> On Wed, Feb 16, 2022 at 7:35 AM Lukasz Luba <lukasz.luba@arm.com> wrote:
>>>
>>> Hi Matthias,
>>>
>>> On 2/9/22 10:17 PM, Matthias Kaehlcke wrote:
>>>> On Wed, Feb 09, 2022 at 11:16:36AM +0000, Lukasz Luba wrote:
>>>>>
>>>>>
>>>>> On 2/8/22 5:25 PM, Matthias Kaehlcke wrote:
>>>>>> On Tue, Feb 08, 2022 at 09:32:28AM +0000, Lukasz Luba wrote:
>>>>>>>
>>>>>>>
>>>
>>> [snip]
>>>
>>>>>>> Could you point me to those devices please?
>>>>>>
>>>>>> arch/arm64/boot/dts/qcom/sc7180-trogdor-*
>>>>>>
>>>>>> Though as per above they shouldn't be impacted by your change, since the
>>>>>> CPUs always pretend to use milli-Watts.
>>>>>>
>>>>>> [skipped some questions/answers since sc7180 isn't actually impacted by
>>>>>> the change]
>>>>>
>>>>> Thank you Matthias. I will investigate your setup to get better
>>>>> understanding.
>>>>
>>>> Thanks!
>>>>
>>>
>>> I've checked those DT files and related code.
>>> As you already said, this patch is safe for them.
>>> So we can apply it IMO.
>>>
>>>
>>> -------------Off-topic------------------
>>> Not in $subject comments:
>>>
>>> AFAICS based on two files which define thermal zones:
>>> sc7180-trogdor-homestar.dtsi
>>> sc7180-trogdor-coachz.dtsi
>>>
>>> only the 'big' cores are used as cooling devices in the
>>> 'skin_temp_thermal' - the CPU6 and CPU7.
>>>
>>> I assume you don't want to model at all the power usage
>>> from the Little cluster (which is quite big: 6 CPUs), do you?
>>> I can see that the Little CPUs have small dyn-power-coeff
>>> ~30% of the big and lower max freq, but still might be worth
>>> to add them to IPA. You might give them more 'weight', to
>>> make sure they receive more power during power split.
>
> In experiments we saw that including the little cores as cooling
> devices for 'skin_temp_thermal' didn't have a significant impact on
> thermals, so we left them out.
I agree, that was also my conclusion after doing some measurements.
Basically, the little cores are always cold and are victims of the big
cores heat dissipation.
They of course contribute a bit to the heat but capping their
performance does not change the temperature trend of the whole.
That is less true with silver-gold were it is the same micro-arch but
different frequencies.
>>> You also don't have GPU cooling device in that thermal zone.
>>> Based on my experience if your GPU is a power hungry one,
>>> e.g. 2-4Watts, you might get better results when you model
>>> this 'hot' device (which impacts your temp sensor reported value).
>>
>> I think the two boards you point at (homestar and coachz) are just the
>> two that override the default defined in the SoC dtsi file. If you
>> look in sc7180.dtsi you'll see 'gpuss1-thermal' which has a cooling
>> map. You can also see the cooling maps for the littles.
>
> Yep, plus thermal zones with cooling maps for the big cores.
>
>> I guess we don't have a `dynamic-power-coefficient` for the GPU,
>> though? Seems like we should, but I haven't dug through all the code
>> here...
>
> To my knowledge the SC7x80 GPU doesn't register an energy model, which is
> one of the reasons the GPU wasn't included as cooling device for
> 'skin_temp_thermal'.
--
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next prev parent reply other threads:[~2022-02-17 9:59 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-07 7:30 [PATCH 0/2] Ignore Energy Model with abstract scale in IPA and DTPM Lukasz Luba
2022-02-07 7:30 ` [PATCH 1/2] thermal: cooling: Check Energy Model type in cpufreq_cooling and devfreq_cooling Lukasz Luba
2022-02-08 0:50 ` Matthias Kaehlcke
2022-02-08 9:32 ` Lukasz Luba
2022-02-08 17:25 ` Matthias Kaehlcke
2022-02-09 11:16 ` Lukasz Luba
2022-02-09 22:17 ` Matthias Kaehlcke
2022-02-16 15:35 ` Lukasz Luba
2022-02-16 17:33 ` Doug Anderson
2022-02-16 22:13 ` Matthias Kaehlcke
2022-02-16 22:43 ` Lukasz Luba
2022-02-17 0:26 ` Matthias Kaehlcke
2022-02-17 10:15 ` Daniel Lezcano
2022-02-17 9:59 ` Daniel Lezcano [this message]
2022-02-17 10:10 ` Daniel Lezcano
2022-02-17 10:47 ` Lukasz Luba
2022-02-17 11:28 ` Daniel Lezcano
2022-02-17 12:11 ` Lukasz Luba
2022-02-17 12:33 ` Daniel Lezcano
2022-02-17 12:37 ` Lukasz Luba
2022-02-17 16:46 ` Matthias Kaehlcke
2022-02-17 16:37 ` Doug Anderson
2022-02-17 17:14 ` Matthias Kaehlcke
2022-02-17 18:05 ` Lukasz Luba
2022-02-17 18:27 ` Daniel Lezcano
2022-02-16 17:21 ` Doug Anderson
2022-02-16 23:28 ` Lukasz Luba
2022-02-17 16:50 ` Doug Anderson
2022-02-17 17:58 ` Lukasz Luba
2022-02-17 18:18 ` Lukasz Luba
2022-02-22 17:05 ` Lukasz Luba
2022-02-22 18:12 ` Daniel Lezcano
2022-02-22 18:31 ` Lukasz Luba
2022-02-22 22:10 ` Daniel Lezcano
2022-02-23 9:10 ` Lukasz Luba
2022-02-07 7:30 ` [PATCH 2/2] powercap: DTPM: Check Energy Model type for power values scale Lukasz Luba
2022-02-07 10:41 ` [PATCH 0/2] Ignore Energy Model with abstract scale in IPA and DTPM Daniel Lezcano
2022-02-07 11:44 ` Lukasz Luba
2022-02-08 7:39 ` Daniel Lezcano
2022-02-08 9:47 ` Lukasz Luba
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