[Solved] How to remove default "performance" CPU-scaling governor.

robotrobert · 2012-02-21 20:24:41

I was goin' trough the cpu scaling wiki and i was able to add the ondemand
cpu scaling governor and the appropriate powerdriver with modprobe command.
Then the cpu speed was lowered as it should so i've added these two to the modules section in rc.conf as well, to start at boot.
After reboot cpufreq-info's output says that both governor is loaded, BUT it doesn't switch to ondemand mode.
1. How can I remove the performance mode?
2. Or is there a possibility to setup it somehow that it switches to ondemand only if i switch to battery mode?
3. Other problem was for me that

find /sys/devices/ -name ondemand

doesn't give back anything, so i cannot lower ondemands governor scaling limit. Where should be these settings?

Now cpufreq-info output:

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  driver: powernow-k8
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 1000 ns.
  hardware limits: 750 MHz - 1.50 GHz
  available frequency steps: 1.50 GHz, 1.20 GHz, 750 MHz
  available cpufreq governors: ondemand, performance
  current policy: frequency should be within 750 MHz and 1.50 GHz.
                  The governor "performance" may decide which speed to use
                  within this range.
  current CPU frequency is 1.50 GHz.

Last edited by robotrobert (2012-02-21 23:09:26)

Raynman · 2012-02-21 20:30:48

Not sure about 3, but everything else is covered in the wiki article linked by you.

Configuring CPU scaling is a 3-part process:
1. Load appropriate CPU frequency driver
2. Load desired scaling governor(s)
3. Select a method to manage switching and tuning governor(s):

You stopped after the second part.

vwyodajl · 2012-02-21 21:49:42

I use this on my i7 for switching, which is found in the wiki as well

for i in 0 1 2 3 4 5 6 7; do sudo cpufreq-set -c $i -g ondemand; done

Adjust it to how many cores your system uses and it will change all to the ondemand scale. You could turn it into a script if you want to make it quick and simple or even keybind it.
HTH

Last edited by vwyodajl (2012-02-21 21:50:24)

robotrobert · 2012-02-21 23:07:04

Raynman wrote:

Not sure about 3, but everything else is covered in the wiki article linked by you.
Configuring CPU scaling is a 3-part process:
1. Load appropriate CPU frequency driver
2. Load desired scaling governor(s)
3. Select a method to manage switching and tuning governor(s):
You stopped after the second part.

Ye, you were right. After i didn't found that folder i was looking for i didn't continue on it.
Turns out, if u use:

echo "ondemand" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

It makes that folder, and u can access all those treshold variables.
But when just running first:

modprobe cpufreq_ondemand

the folder for ondemand won't be created. Im sure this is logical, i'm just new to the whole logic of this.
After modifying tresholds, i've installed laptop-mode, and I need to say, it really k*cks *ss. You can set everythin u want, and it runs along fine in a daemon, using for example: acpid for checking battery state, hdparm for setting power/spinning of hard disks...
I just leave another wiki link here if someone gets here...
LAPTOP-MODE TOOLS

There's still a not-releated question here, how come i cannot edit as a superuser directly these file under /sys/devices/system/cpu ? I know that these meant to be edited by the system, but still i tought if i'm root, i modify what i want...
( I know that I can assign parameters to these files with edit -n <number> > <filename> )

Last edited by robotrobert (2012-02-21 23:08:55)

vwyodajl · 2012-02-21 23:19:16

edit:
Removed incorrect info. Sorry about that forgot that point

Last edited by vwyodajl (2012-02-21 23:58:22)

Gusar · 2012-02-21 23:26:22

@vwyodajl: sysctl is for /proc/sys, not for /sys

@robotrobert: The reason you can't edit those files is because they aren't actually files. /sys is a virtual filesystem.

robotrobert · 2012-02-22 11:42:14

Gusar wrote:

@vwyodajl: sysctl is for /proc/sys, not for /sys
@robotrobert: The reason you can't edit those files is because they aren't actually files. /sys is a virtual filesystem.

I see, thx for clarifying. I will need to dig myself into linux directories / kernel docs to get the "bigger" picture.

Arch Linux

#1 2012-02-21 20:24:41

[Solved] How to remove default "performance" CPU-scaling governor.

#2 2012-02-21 20:30:48

Re: [Solved] How to remove default "performance" CPU-scaling governor.

#3 2012-02-21 21:49:42

Re: [Solved] How to remove default "performance" CPU-scaling governor.

#4 2012-02-21 23:07:04

Re: [Solved] How to remove default "performance" CPU-scaling governor.

#5 2012-02-21 23:19:16

Re: [Solved] How to remove default "performance" CPU-scaling governor.

#6 2012-02-21 23:26:22

Re: [Solved] How to remove default "performance" CPU-scaling governor.

#7 2012-02-22 11:42:14

Re: [Solved] How to remove default "performance" CPU-scaling governor.

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