[sf-lug] Overheating and CPU throttling

[Ken Shaffer]

grep the /var/log/kern.log for temp, and see if throttling occurs.  It
does on my 4.15 kernel for Ubuntu 18.04. I think you were on the right
track looking for dust, but check the whole air-flow path-- dust can
clog any input filter, and labels may dry out and pop off, blocking
the outlet.Check the fan speed with the sensors command, If it's not
full speed, maybe it's wearing out.  Investing in a hypodermic of high
quality thernal paste could help a cpu, particularly if just a piece
of thermal tape was used for the conductivity. External cooling
fan/pad might help too for a low cost.
Ken

On 1/12/19, Akkana Peck <akkana at shallowsky.com> wrote:
> My Thinkpad X201 laptop has developed an overheating problem.
> Randomly, when I'm doing something lengthy and CPU intensive
> like building Firefox, it will shut down without warning. Afterward,
> I have messages like this in /var/log/kern.log:
> thermal_zone0: critical temperature reached (100 C), shutting down
>
> I've found lots of pages with people with similar problems,
> getting lots of responses like "Any modern Linux computer should
> automatically throttle its CPU when temperatures get high". No one
> explains how this automatic throttling is supposed to happen, or how
> to enable it if it's not happening, or what "modern" means (is it
> the CPU that needs to be modern? The BIOS? The kernel? How modern?)
>
> What I'd really like is a daemon or kernel setting that monitors
> the temperature and, if it exceeds max (well before it reaches
> critical), scales down the CPU frequency, or kills or (preferably)
> suspends whatever process is running away with the CPU, or suspends
> the machine rather than shutting down. I have started down the path
> of writing such a daemon, but it's complicated by not wanting to
> suspend certain processes like X even if their CPU usage looks high
> due to some other app. And it's hard to believe Linux doesn't
> already offer a solution to this problem.
>
> More system details:
>
> This X201 has been my main workhorse for 5+ years and never had
> temperature problems until a few weeks ago. I have opened it
> and don't see any dust bunnies around the fan.
>
> Processor is a quad-core Intel(R) Core(TM) i5 CPU M 540 @ 2.53GH.
> Distro is Debian Testing. Kernel was 4.18.0-2-amd64, which I was
> stuck on because of a modeset bug in 4.18.0-3, but it looks like
> 4.19.0-1 has fixed it so now I've upgraded.
>
> /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor is
> "ondemand", if that matters; though it doesn't seem from
> https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
> like any of the governors look at temperature at all.
>
> Any suggestions? Any good articles I could read on how this
> scaling/governor/thermal/cpufreq stuff is supposed to work?
>
>         ...Akkana
>
> _______________________________________________
> sf-lug mailing list
> sf-lug at linuxmafia.com
> http://linuxmafia.com/mailman/listinfo/sf-lug
> SF-LUG is at http://www.sf-lug.org/
>