devicetree.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Lukasz Luba <lukasz.luba@arm.com>
To: Rob Herring <robh@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	vireshk@kernel.org, sboyd@kernel.org, nm@ti.com,
	rafael@kernel.org, sudeep.holla@arm.com,
	daniel.lezcano@linaro.org, Dietmar.Eggemann@arm.com
Subject: Re: [PATCH 1/4] dt-bindings: opp: Introduce opp-sustainable bindings
Date: Mon, 2 Nov 2020 08:40:57 +0000	[thread overview]
Message-ID: <569a07c0-be6b-7ffe-2920-accea1f932f0@arm.com> (raw)
In-Reply-To: <20201030193427.GA4186428@bogus>

Hi Rob,

On 10/30/20 7:34 PM, Rob Herring wrote:
> On Wed, Oct 28, 2020 at 02:08:44PM +0000, Lukasz Luba wrote:
>> Add opp-sustainable as an additional property in the OPP node to describe
>> the sustainable performance level of the device. This will help to
>> estimate the sustainable performance of the whole system.
>>
>> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
>> ---
>>   Documentation/devicetree/bindings/opp/opp.txt | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
>> index 9847dfeeffcb..cd01028de305 100644
>> --- a/Documentation/devicetree/bindings/opp/opp.txt
>> +++ b/Documentation/devicetree/bindings/opp/opp.txt
>> @@ -154,6 +154,10 @@ Optional properties:
>>   - opp-suspend: Marks the OPP to be used during device suspend. If multiple OPPs
>>     in the table have this, the OPP with highest opp-hz will be used.
>>   
>> +- opp-sustainable: Marks the OPP as sustainable. This property can be used for
>> +  estimating sustainable performance of the whole system. If multiple OPPs in
>> +  the table have this, the OPP with highest opp-hz will be used.
>> +
> 
> Isn't this just the inverse of the turbo? or boost? flag we already
> have?

True, it could be possible to use those flags. Then a function which
returns one OPP below, would be 'sustainable'. I've already
suggested to skip binding and only have get/set functions for OPP
framework to mark 'sustainable' level, but Viresh is against.
We have discussed this new opp sustainable with Viresh and since it
would be only used by IPA but the definition is a bit blurry,
we decided to drop this series. Maybe in future when there will be
another user, we will come back to this.
I am going to use Energy Model and mark the em_perf_state as sustained.

> 
> Couldn't this be learned? I ran at this frequency and then overheated.
> That could be dependent on ambient temperatures or dust build up on
> fans/heatsink.

Yes it could be learned. IPA tries to do that for different workloads,
but it needs some starting conditions (coefficients and sustainable
power) to converge in short time. Sustainable power is currently
estimated based on lowest OPP. With that new 'sustainable' flag,
it would be much easier for IPA to converge.

Regards,
Lukasz

> 
> Rob
> 

  reply	other threads:[~2020-11-02  8:41 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-28 14:08 [PATCH 0/4] Add sustainable OPP concept Lukasz Luba
2020-10-28 14:08 ` [PATCH 1/4] dt-bindings: opp: Introduce opp-sustainable bindings Lukasz Luba
2020-10-28 21:47   ` Nishanth Menon
2020-10-29 10:04     ` Lukasz Luba
2020-10-29 12:59       ` Nishanth Menon
2020-10-29 13:33         ` Lukasz Luba
2020-10-29 13:49           ` Nishanth Menon
2020-10-29 14:20             ` Lukasz Luba
2020-10-30 19:34   ` Rob Herring
2020-11-02  8:40     ` Lukasz Luba [this message]
2020-10-28 14:08 ` [PATCH 2/4] OPP: Add support for parsing the 'opp-sustainable' property Lukasz Luba
2020-10-30 11:47   ` Quentin Perret
2020-10-30 12:53     ` Lukasz Luba
2020-10-28 14:08 ` [PATCH 3/4] OPP: Add dev_pm_opp_set_sustainable_opp_freq() Lukasz Luba
2020-10-28 14:08 ` [PATCH 4/4] firmware: arm_scmi/perf: Mark sustainable OPP Lukasz Luba
2020-10-29  7:40 ` [PATCH 0/4] Add sustainable OPP concept Viresh Kumar
2020-10-29  7:53   ` Viresh Kumar
2020-10-29  9:56     ` Lukasz Luba
2020-10-30  8:29       ` Viresh Kumar
2020-10-30  9:19         ` Lukasz Luba
2020-10-30  9:52           ` Viresh Kumar
2020-10-30 10:56             ` Lukasz Luba
2020-10-30 11:17               ` Viresh Kumar
2020-10-30 12:40                 ` Lukasz Luba

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=569a07c0-be6b-7ffe-2920-accea1f932f0@arm.com \
    --to=lukasz.luba@arm.com \
    --cc=Dietmar.Eggemann@arm.com \
    --cc=daniel.lezcano@linaro.org \
    --cc=devicetree@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=nm@ti.com \
    --cc=rafael@kernel.org \
    --cc=robh@kernel.org \
    --cc=sboyd@kernel.org \
    --cc=sudeep.holla@arm.com \
    --cc=vireshk@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).