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Linux - Laptop and Netbook Having a problem installing or configuring Linux on your laptop? Need help running Linux on your netbook? This forum is for you. This forum is for any topics relating to Linux and either traditional laptops or netbooks (such as the Asus EEE PC, Everex CloudBook or MSI Wind).

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Old 03-04-2008, 09:27 AM   #1
dda
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Registered: May 2004
Location: Rostov-on-Don, Russia
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Occasional CPU frequency scaling problems on AMD Turion


Hello,

I have an MSI M635 Megabook laptop, with Ubuntu Gutsy (kernel 2.6.22-14). After installation, powernowd and module powernow_k8 was installed automatically, and CPU frequency monitor in Gnome shows frequency changing from 800MHz to 2GHz depending on load. But after some (up)time (2-3 days), it starts to show 800MHz only, and I notice that PC becomes slow. I checked and found that /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq and /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq both contain 800000. When scaling works correctly, scaling_max_freq contains 2000000, as expected. I tried to unload and reload modules (powernow_k8, freq_table, cpufreq_powersave) - but after I load them back, again I see 800000 in both files, and scaling does not work. Is it a buggy bios, or what?

Thanks!
Dmitry.
 
Old 03-07-2008, 06:25 AM   #2
biophysics
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Registered: Jan 2002
Location: Germany
Distribution: Kubuntu
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First when your machine is working normally (frequency changing) check:
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

When is becomes very slow check the same:
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor


For the recent kernels you do not need powernowd. Just uninstall powernowd and (reboot) see what is the governor. (I also do not use it)

/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver

I think the preferred governor for Turion is conservative (google for kernel documentation). There different possibilites for the problem:

1. powernowd changes the governor to powersave after sometime (constant = 800 Mhz)
2. powernowd is unable to reload ondemand
3. powernowd crashed

Try to use conservative (permanently):
sudo su -
echo conservative > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

Can you post the output of /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors

immediately after booting the machine, after running it in battery, inserting the laptop charger... Try various combinations to see what happens.
 
Old 03-08-2008, 03:29 AM   #3
dda
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Registered: May 2004
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Thank you for detailed info! I will follow your recommendations if it fail again I suspected that the problems began since I installed and run GKrellM (not immediately after running it, but after some time of GKrellM being run). After last reboot I did not start it, and CPU works correctly since then (4 days).

When CPU was locked at 800MHz, the files contents were:

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors <==
userspace conservative performance

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq <==
800000

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver <==
powernow-k8

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor <==
userspace

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq <==
800000

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq <==
800000

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed <==
800000



Now, when it works good, they are:

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors <==
conservative userspace ondemand powersave performance

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq <==
800000

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver <==
powernow-k8

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor <==
ondemand

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq <==
2000000

==> /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq <==
800000


Thanks again!
Dmitry.
 
Old 03-09-2008, 12:22 PM   #4
biophysics
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Registered: Jan 2002
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Perhaps you have a CPU freq modifier plugin in gkrellm which interferes. (I really doubt that) In case you have one remove that plugin and leave the kernel to decide.

Or more likely there is a problem with ondemand governor (for your kernel and hardware config). I would say switch to conservative and leave it like that forever.
 
  


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