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:

quoted

On Fri 2016-11-04 09:38:49, Pavel Machek wrote:

quoted

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.

quoted

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.

quoted

/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.

quoted

/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.

quoted

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.

-- 
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html