Hi Douglas,
On 9/30/20 12:53 AM, Doug Anderson wrote:
Hi,
On Tue, Sep 29, 2020 at 5:16 AM Lukasz Luba <lukasz.luba@xxxxxxx> 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@xxxxxxx>
---
.../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@xxxxxxxxxxxx>
Thank you for the review.
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?
For completeness, we are talking here about the binding from:
Documentation/devicetree/bindings/arm/cpus.yaml
which is 'dynamic-power-coefficient'. Yes, it stays untouched, also the
unit (uW/MHz/V^2) which then allows to have mW in the power
values in the EM.
Regards,
Lukasz
