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[v3,4/4] Documentation: EM: Describe new registration method using DT

Message ID 20220224081131.27282-5-lukasz.luba@arm.com
State Superseded
Headers show
Series Introduce "opp-microwatt" and 'advanced' Energy Model from DT | expand

Commit Message

Lukasz Luba Feb. 24, 2022, 8:11 a.m. UTC
The new registration method allows to get power values from the DT OPP
definition. The new OPP entry property "opp-microwatt" contains total
power expressed in micro-Watts. Align the EM documentation with this
new possible registration method of 'advanced' EM.

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
---
 Documentation/power/energy-model.rst | 10 ++++++++++
 1 file changed, 10 insertions(+)

Comments

Lukasz Luba Feb. 24, 2022, 9:39 a.m. UTC | #1
On 2/24/22 09:37, Viresh Kumar wrote:
> On 24-02-22, 09:25, Lukasz Luba wrote:
>> Our partners had a lot of issues with EM+EAS, because they were not
>> aware of the internals of EM and limitations.
>>
>> We've started to name two types of EM: 'advanced' and 'simple'.
>> The 'simple' is the one which causes issues. Now when we contact with
>> partners we ask if they use 'simple' EM and see some issues in EAS.
>> This is a needed clarification and naming convention that we use.
>>
>> Here the paragraph name is stressing the fact explicitly that
>> from today we have the option to provide real power measurements using
>> DT and it will be the 'advanced' EM.
> 
> I understand the background now, and since I am part of the same
> community I can appreciate that. But being a maintainer, I have to say
> that when we look at something from Upstream's point of view, we may
> have to neglect/ignore the terminology used in downstream.

I understand your upstream point of view.

> 
>  From what I can see, there is no advancement here, as of now. This is
> a very small change where we are getting pre-evaluated power values
> from DT, instead of calculating them at runtime. The data may be more
> correct, but the EM doesn't get advanced because of that. And so using
> such terminology is only going to harm further. If EM gets a
> "advanced" algorithm later on, which can improve things, then yes we
> can call it advanced, but for now there is nothing.
> 

Fair enough, I'll drop this word from the paragraph name.
diff mbox series

Patch

diff --git a/Documentation/power/energy-model.rst b/Documentation/power/energy-model.rst
index 5ac62a7b4b7c..719253fd5215 100644
--- a/Documentation/power/energy-model.rst
+++ b/Documentation/power/energy-model.rst
@@ -113,6 +113,16 @@  to: return warning/error, stop working or panic.
 See Section 3. for an example of driver implementing this
 callback, or Section 2.4 for further documentation on this API
 
+Registration of 'advanced' EM using DT
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The 'advanced' EM can also be registered using OPP framework and information
+in DT "operating-points-v2". Each OPP entry in DT can be extended with a
+property "opp-microwatt" containing micro-Watts power value. This OPP DT
+property allows a platform to register EM power values which are reflecting
+total power (static + dynamic). These power values might be coming directly
+from experiments and measurements.
+
 Registration of 'simple' EM
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~