Am Mon, 21 Mar 2022 16:31:42 +0100
schrieb Matthias Schmidt <[email protected]>:

> Hi,
> 
> * Solene Rapenne wrote:
> > I'm proposing a very simple change to the automatic policy of the
> > CPU frequency scheduler.
> > 
> > Currently, every 100ms the scheduler is doing this:
> > 
> > - when the CPU load exceeds the threshold, CPU frequency is set to
> > the maximum and the variable downbeats is set to 5.
> > - when the CPU load is below the threshold, downbeats is
> > decremented, if it's == 0 then the CPU load is reduced to 0
> > 
> > my proposal is to change the downbeat to be adaptive to the load,
> > instead of setting it to 5 all the time, I propose to increment it
> > with a limit of 5. Instead of having the frequency set at max for
> > 500ms (5 cycles) every time the CPU usage is above the treshold, we
> > will keep the frequency high for a number of cycles depending how
> > long it was high (up to 5). So, in case of short CPU usage burst
> > like opening a new MP3 file for decoding or a click on a GUI, we
> > have a frequency burst of 100ms instead of 500ms.
> > 
> > I've been using it for a few days, I noticed a huge battery life
> > improvement with no responsiveness change.
> 
> I have the patch running since the weekend (when it was first shared)
> and noticed that my CPU on battery spins up less often than before.  I
> have the feeling that my battery lasts longer, however, I need to do
> some more measurements to have a proof.

I've tried the patch and can confirm this on my old netbook. The fan
spins considerably less often, the system feels a bit more responsive
and the battery seems to last longer.

At this point in time I cannot tell how much longer the battery lasts
exactly, but even quieter fan alone makes the patch worthwile for me.

Thank you Solene!

-- 
greetings,

Florian Viehweger

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