A deeper insight into frequencies, voltages & a thermal script

[johnicboom]

You are right, I tested this.
This is probably the way to go, if we already have cpufrequtils installed

Since that /etc/init.d/cpufrequtils file includes this after the default setting:
if [ -f /etc/default/cpufrequtils ] ; then . /etc/default/cpufrequtils

Is it not better to set it there like I did initially so that setting survives any updates to cpufrequtils?

You do need to reboot for this to take effect.

Also, I mis-copied my /etc/default/cpufrequtils contents... very sorry about that! It needs to be
ENABLE="true"
not
ENABLE="false"
I edited my original post to not give out the wrong info, but here is the correct contents again:
ENABLE="true" GOVERNOR="conservative" MAX_SPEED=0 MIN_SPEED=0

 

[Askarus]

Since that /etc/init.d/cpufrequtils file includes this after the default setting:
if [ -f /etc/default/cpufrequtils ] ; then . /etc/default/cpufrequtils

Is it not better to set it there like I did initially so that setting survives any updates to cpufrequtils?

You do need to reboot for this to take effect.

Also, I mis-copied my /etc/default/cpufrequtils contents... very sorry about that! It needs to be
ENABLE="true"
not
ENABLE="false"
I edited my original post to not give out the wrong info, but here is the correct contents again:
ENABLE="true" GOVERNOR="conservative" MAX_SPEED=0 MIN_SPEED=0

Hahaha, I just was confused about this. It did not work unless I set ENABLED to "true".

Yeah, your option is the best probably.
I guess we can leave out all content from that file, except for that one line regarding the givernor.

 

[netcat]

I honestly think that our custom governor might be the best option.

We could have a governor that only scales up the frequency for interactive processes.
Seems to be exactly what we want?

 

[johnicboom]

Hahaha, I just was confused about this. It did not work unless I set ENABLED to "true".

Yeah, your option is the best probably.
I guess we can leave out all content from that file, except for that one line regarding the givernor.

Yes, I can confirm we only need the
GOVERNOR="conservative"
line for it to work once you reboot.

 

[Askarus]

I edited the first post and added the cpufrequtils file.
Thanks for your help netcow and johnicboom.

 

[johnicboom]

I built my own device tree based on yours, Askarus, and made these changes:
/* kHz uV */ 50000 730000 100000 730000 150000 730000 200000 750000 250000 750000 300000 750000
Now I feel like I kind of cheated myself and should have gone for lower voltages at more frequencies, but I'll keep it here for a while and see if it's stable.

 

[Askarus]

I built my own device tree based on yours, Askarus, and made these changes:
/* kHz uV */ 50000 730000 100000 730000 150000 730000 200000 750000 250000 750000 300000 750000
Now I feel like I kind of cheated myself and should have gone for lower voltages at more frequencies, but I'll keep it here for a while and see if it's stable.

All the other frequencies are still the bare minimum numbers that made 10 Pyras boot. It was just the lower frequencies that I had to increase.
I expect instability if you lower those other voltages by more than 10mV.
You should definitely test that on a boot SD first.

Except for 250MHz, I would not recommend you to lower beyond those values:

&cpu0 {
    operating-points = <
        /* kHz    uV */
         250000  670000
         375000  730000
         500000  770000
         625000  770000
         750000  810000
         875000  860000
        1000000  920000
        1125000  960000
        1250000 1010000
        1400000 1080000
        1500000 1130000
    >;
};

Sure, do whatever you want and test your luck. I already lowered the voltages for all other frequencies by more than 100mV (less below 500MHz).

Those are the defaults in comparison:

   Hz        uV
 250000  750000
 375000  800000
 500000  850000
 625000  900000
 750000  950000
 875000 1000000
1000000 1050000
1125000 1075000
1250000 1100000
1400000 1200000
1500000 1250000
1600000 1300000
1700000 1350000
1800000 1350000
1900000 1350000
2000000 1450000

Calculate the percentage by which I reduced the voltage per frequency already and decide if 10mV less are worth all the trouble
Frequencies below 250MHz are an exemption to this, everything else is very most likely not worth it.

 

[johnicboom]

Ah, right. I see what you mean. Since everything was fine, I dropped to
/* kHz uV */
50000 700000
100000 700000
150000 700000
200000 700000
250000 750000
300000 750000

It froze at 100 MHz pretty much right after booting. I'll just go back to your original modifications and stick with that for now. I'm not being careful enough or targeted enough in my testing for it to really be worth much, anyway. It was cool to try, though. Now at least I know how I can change something in the device tree if there's anything we want tested.