Re: [PATCH 1/2] docs: Clarify abstract scale usage for power values in Energy Model

Doug Anderson
2020-09-29T23:53:34Z

Hi,

On Tue, Sep 29, 2020 at 5:16 AM Lukasz Luba <lukasz.luba@arm.com> wrote:
>
> The Energy Model (EM) can store power values in milli-Watts or in abstract
> scale. This might cause issues in the subsystems which use the EM for
> estimating the device power, such as:
> - mixing of different scales in a subsystem which uses multiple
> (cooling) devices (e.g. thermal Intelligent Power Allocation (IPA))
> - assuming that energy [milli-Joules] can be derived from the EM power
> values which might not be possible since the power scale doesn't have to
> be in milli-Watts
>
> To avoid misconfiguration add the needed documentation to the EM and
> related subsystems: EAS and IPA.
>
> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
> ---
> .../driver-api/thermal/power_allocator.rst | 8 ++++++++
> Documentation/power/energy-model.rst | 13 +++++++++++++
> Documentation/scheduler/sched-energy.rst | 5 +++++
> 3 files changed, 26 insertions(+)

I haven't read through these files in massive detail, but the quick
skim makes me believe that your additions seem sane. In general, I'm
happy with documenting reality, thus:

Reviewed-by: Douglas Anderson <dianders@chromium.org>

I will note: you haven't actually updated the device tree bindings.
Thus, presumably, anyone who is specifying these numbers in the device
tree is still supposed to specify them in a way that mW can be
recovered, right? Said another way: nothing about your patches makes
it OK to specify numbers in device trees using an "abstract scale",
right?

-Doug