notebook cpu throttling [solved]

[Ghirai]

> [..]
 >>  >> I did that, but now xorg constantly uses 20-30% CPU.
 >>  >> 
 >>  >> CPUs were running cooler indeed, but everything ran jerky,
 >>  >> because of the xorg cpu usage.
> [..]
 >> > Point being, if powerd has selected your lowest cpu frequency because
 >> > load is less than default (or as specified by -i and -r switches) and
 >> > this is (say) 1/4 of full speed, then something that normally showed 5%
 >> > cpu will now show as using 20% (of available cpu cycles at that speed)
 >> 
 >> > You can tune your powerd idle levels more towards performance, and/or
 >> > you can set a higher minimum cpu freq with sysctl debug.cpufreq.lowest
 >> > from among your available levels.
> [..]

 >> I suspected this; xorg just reporting to use 20-30% cpu doesn't bother
 >> my, what bothers me is the fact that mouse cursor and everything moves
 >> jerky.
 >> 
 >> I'll try to raise the min. freq., maybe powerd lowers it too much..

> Maybe.  In one recent example, a 1400MHz box (Thinkpad T42p) had freqs
> all the way down to 75MHz while still running with 1mS slicing (1000HZ)
> apparently losing i8254 timer interrupts (when using APM, not with ACPI)

> powerd(8) in adaptive mode with default settings will lower cpu freq one
> level whenever the load idle is 90% or more, and raise freq (two levels)
> whenever idle gets less than 65%.  Looks like if you set that to say 75%
> your xorg alone would kick it up.  Of course you must be careful not to
> set the shiftpoints too close together, or you'll observe oscillation ..
> again, running 'powerd -v' is useful while you're playing with tuning.

> Re jerkiness, you might also benefit by decreasing the polling interval
> (how often powerd checks load average) from 500mS to perhaps half that?

> I'm kinda interested in these fujitsu-siemens laptops myself, so I'm
> still keen to see your 'sysctl dev.cpu.0.freq_levels' please? 

> Cheers, Ian



Ok, i think i got it working.

dev.cpu.0.freq_levels showed about 14 possibilities.

It turned out that powerd was lowering it down to 100MHz,
or 50MHz per core.

Playing with debug.cpufreq.lowest, i increased it gradually
until KDE/Xorg behaved normal; for my system it was 800MHz,
which is 400MHz/core.

-- 
Best regards,
Ghirai.