Hi!
> I am really confused about where the problem is. 4.8 or 4.9 ? :)
Well, v4.8 runs at too low frequency without explanation, and v4.9
overheats. Both are a problem :-). But it starts to look like v4.9 is
the one where the real problem is.
> On 04-11-16, 09:58, Pavel Machek wrote:
> > On Fri 2016-11-04 09:38:49, Pavel Machek wrote:
> > > Hi!
> > >
> > > I'm debugging overheats on v4.9-rc1... which did not seem to happen in
> > > v4.8-rc1. I'm running basically "nice make -j 3" on kernel... cpus are
> > > fully loaded.
> > >
> > > %Cpu(s): 7.5 us, 18.5 sy, 72.6 ni, 0.0 id, 0.0 wa, 0.0 hi, 1.5
> > > si, 0.0 st
> > > KiB Mem: 3087096 total, 2993076 used, 94020 free, 52900
> > > buffers
> > > KiB Swap: 1681428 total, 60900 used, 1620528 free. 1183664
> > > cached Mem
> > >
> > > Still, cpus don't stay on maximum frequency on v4.8-rc1. (I suspect
> > > that may be why machine does not overheat).
> >
> > What is worse, they go to low frequency even with "performance"
> > governor on v4.8-rc1?!
>
> You sure about it? How did you check it?
See the dumps below. cpuinfo_cur_freq shows 1GHz while compilation is running.
> Also why are you testing on 4.8-rc1? And not a 4.8 stable kernel? What if the
> core is already fixed upstream ?
>
> There is one core fix in 4.8:
>
> commit 899bb6642f2a ("cpufreq: skip invalid entries when searching the
> frequency")
Ok, I guess that's not it.
> > 1000000
> > 1000000
>
> Is this happening because of thermal capping ? That is the only reason that I
> could think of where freq can change with performance governor.
How would I know if it is thermal capping? There's nothing in dmesg.
> > /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq:1000000
> > /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver:acpi-cpufreq
> > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor:performance
> > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq:1000000
>
> And this value sort of confirms it.
>
> > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq:1000000
> > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed:<unsupported>
> > grep: /sys/devices/system/cpu/cpu0/cpufreq/stats: Is a directory
> > pavel@duo:/sys/devices/system/cpu/cpu0/cpufreq$
> >
> > Let me try v4.9-rc2... that works ok (cpus at the high frequency
> > during the kernel build). Unfortunately that sends my cpus to 99C
> > temperature range (and eventually forces emergency shutdown).
>
> Unbelievable.
>
> > v4.9-rc2, current policy changes without me touching it. Notice the
> > 1.47GHz below? I did not do that, it oscilates itself. Is that thermal
> > protection?
>
> Looks like to me.
>
> Can we verify somehow about what's the situation should look like? Perhaps with
> some older stable kernel? And then see if 4.8.X works fine or 4.9-rc.
I can try older kernel from Debian distribution, I guess.
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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