issues with powerd/freq_levels

[Ian Smith]

On Mon, 31 Jul 2017 10:09:11 +0300, Daniel Braniss wrote:

 > I am trying out PCengines latest apu2 boards, and I just noticed that with different Freebsd versions I get
 > different freq_levels, and so when idling, each box (have 5) has a different	freq/temperature value, ranging
 > from 125/69.1C, 600/59.0C to 75/56.0C
 > 
 > FreeBSD apu-4 11.1-STABLE FreeBSD 11.1-STABLE #5 f565b5a06ab3 (11) tip: Mon Jul 31 09:36:33 IDT 2017
 > apu-4# sysctl dev.cpu.0.freq_levels
 > dev.cpu.0.freq_levels: 1000/980 800/807 600/609

That looks about right.  On a Core2Duo (still on 9.3) I get:
dev.est.1.freq_settings: 2401/35000 2400/35000 1600/15000 800/12000
dev.est.0.freq_settings: 2401/35000 2400/35000 1600/15000 800/12000
dev.cpu.0.freq_levels: 2401/35000 2400/35000 1600/15000 800/12000
dev.cpu.0.freq: 800

But only because I'd added to /boot/loader.conf:

hint.p4tcc.0.disabled=1
hint.acpi_throttle.0.disabled=1

which became the defaults sometime, maybe not before 11.0?  Otherwise 
mine would look more similar to the one below, with all 12.5% increments 
in frequency enabled, which doesn't actually save any power at all.

 > FreeBSD apu-5 11.1-PRERELEASE FreeBSD 11.1-PRERELEASE #0 21e9d1ca9b80 (11) tip: Tue May 30 11:51:48 IDT 2017
 > apu-5# sysctl dev.cpu.0.freq_levels
 > dev.cpu.0.freq_levels: 1000/966 875/845 800/795 700/695 600/600 525/525 450/450 375/375 300/300 225/225 150/150 75/75

Looks like either p4tcc or acpi_throttle is enabled?  See cpufreq(4).
As above, these don't buy you anything but extra busyness for powerd.

Also noticed that the (nice, low!) milliwatt figures for 1000/800/600 
freqs are a bit different to the -stable one.  Slightly Different model?

 > FreeBSD apu-1 10.3-STABLE FreeBSD 10.3-STABLE #4 267788fd852c (10) tip: Tue Jan 10 09:09:00 IST 2017
 > apu-1# sysctl dev.cpu.0.freq_levels
 > dev.cpu.0.freq_levels: 1000/-1 875/-1 750/-1 625/-1 500/-1 375/-1 250/-1 125/-1

And that looks like est(4) isn't enabled/attaching at all .. see dmesg 
on all of these for clues.

 > so, any ideas as to what is going on?

Pure guesswork on experience with older versions, I'm not up to date.

cheers, Ian