Control: tag -1 moreinfo
On Sun, 18 Sep 2016 19:08:32 +0200 Alessio <alga777@gmail.com> wrote:
> 2016-09-18 15:44 GMT+02:00 Ben Hutchings <ben@decadent.org.uk>:
> > Control: tag -1 moreinfo
> >
> > On Sun, 2016-09-18 at 14:46 +0200, Alessio Gaeta wrote:
> >> Package: src:linux
> >> Version: 4.7.2-1+s1
> >> Severity: important
> >>
> >> Hello,
> >>
> >> I'm facing a power issue with the Linux 4.7 kernel.
> >>
> >> Every time the system goes idle (the configured delay passes and the display
> >> goes black), the frequency of all cores get maxed, even if all cores are idle.
> >>
> >> Evident symptoms are the fan spinning loudly and the errors logged in journal
> >> stating the thermal threshold being surpassed and the CPU throttled.
> >>
> >> In detail, the frequency of all cores raises from ~800 MHz to 2.6 GHz for all 8
> >> cores of my i7. I can reproduce the behavior 100% of times, by connecting via
> >> ssh to the affected system and launching powertop.
> >>
> >> The issue does not exists in Linux 4.6 (to wich I will stick for now), so I
> >> guess the problem resides in kernel, not in other packages.
> >>
> >> You have all system information here below (gathered by repotbug). Ask any
> >> further info if needed. Thank you!
> > [...]
> >
> > Please test with bbswitch and acpi_call removed.
>
> Hello,
>
> tested again:
>
> 1. systemctl stop bumblebeed.service
> 2. modprobe -r bbswitch
> 3. modprobe -r acpi_call
> 4. systemctl stop vboxweb.service
> 5. modprobe -r vboxpci vboxnetflt vboxnetadp vboxdrv
>
> (removed all out-of-tree modules, just to be sure).
>
> Same result: on display idle the CPU frequency got maxed on all cores.
>
> Tell me if you need more info.
OK, so something (other than those modules) is keeping the CPUs busy.
Please install linux-perf and use perf (as root) to show what it's busy
with:
perf record -a sleep 10 # creates 'perf.data' in current dir
perf report > perf_report.txt # will show some warnings; don't worry about them
Ben.
--
Ben Hutchings
No political challenge can be met by shopping. - George Monbiot
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