Lower the CPU frequency, permanently....how to do?

Seb74 · 2007-11-20 20:35:22

I just want to know, if its possible, how to lower the frequency of my Athlon64 3000+ permanently to like 1GHz or so, since its more then enough for my server. I'm not 100% sure, but I think all Cool n' Quiet does is lowering the clock, not mess with voltages and stuff, and apparently that is enough to save like 10W or so powerconsumption. Would be nice

Thanks in advance

freigeist · 2007-11-20 20:43:45

Seb74 wrote:

I just want to know, if its possible, how to lower the frequency of my Athlon64 3000+ permanently to like 1GHz or so, since its more then enough for my server. I'm not 100% sure, but I think all Cool n' Quiet does is lowering the clock, not mess with voltages and stuff, and apparently that is enough to save like 10W or so powerconsumption. Would be nice
Thanks in advance

You could use the cpufreq-set -u xxx command to set the max frequency to the lowest value possible (shown by cpufreq-info). cpufreq-info and cpufreq-set are provided by the cpufrequtils package and will only work if the correct modules for your cpu are loaded. But using cpufreq-set -g conservative to choose the conservative governor would be a better way, because the cpu clock will be at the minimum if there is no load but increases with higher load.

Last edited by freigeist (2007-11-20 20:44:14)

Seb74 · 2007-11-20 20:47:39

Thanks, but the reason I didn't want any dynamic Cool n' Quiet solution is they seem so damn messy.
I've read some so called "tutorials" and its the worst mess ever. I also tried it a year ago or so after some help but never worked and I think it just ended in a timeconsuming reinstall.

I would like a simpler method, not installing 3 apps and editing 3 configfiles with some arbitrary lines that depend on 10 different things like kernel, CPU-type, number of cores, version of some package, and so on and so on.

Maybe not possible then? I cant just add one package and run one simple command and have it done, permanently?
Some other OS's that are like 5-6 years old have it working right out of the box....

thayer · 2007-11-20 20:55:31

Check your BIOS if you haven't already done so... except for OEM systems, most motherboards will let you override the clock settings. It doesn't get much simpler than that.

I agree with freigeist though, the cpufreq tool is dead easy and I've never had it get messy or complicated. Simply install the package, and load the governor module and daemon in your rc.conf. You can specify a min/max value in /etc/conf.d/cupfreq and I think you could even set them both to the same value, thus forcing it to be whatever clock you want.

cactus · 2007-11-20 20:56:01

If you are looking for 'out of the box', then you probably want fedora or ubuntu.
If you want to put forth some effort, then arch can do it....in fact, it would probably be a matter of echo'ing the proper strings to the /sys (or is it /proc/sys) targets.

cat something like /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies to get the avail frequencies, and set it with echo statements to /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed (or whatever) in rc.sysinit.

It has been a while since I fiddled with that stuff, and my paths are probably very wrong (pulled from some random site).

Seb74 · 2007-11-20 21:05:29

Well, the thing is, when you search forums and stuff about this, that lots of guys say "do like this, or wait, maybe its like that, or well, it depends on your CPU and some other things, but its easy I promise", and you end up not knowing more than you did before starting to read.

Oh well...if I manage to dig the server out of its place I might connect a keyboard and see if the bios for my nForce3-board might be able to fix it in hardware. THAT would be EASY

Last edited by Seb74 (2007-11-20 21:06:07)

SiD · 2007-11-20 21:30:44

I have to scale down permanently my laptops cpu max_freq because the speedstepping modules are overclocking my cpu.

cactus wrote:

cat something like /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies to get the avail frequencies, and set it with echo statements to /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed (or whatever) in rc.sysinit.

As cactus said, with

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

you get the available freqs of your CPU.

for example:

1600000 1400000 1200000 800000 600000

One of this values is stored in /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

I have this line in /etc/rc.local to set the max_freq on boot.

echo 1400000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

P.S.
I don't know if the pathes are exactly the same on all systems. If the files don't exist on you system check if the Speedstepping kernel modules for your CPU are loaded....

Last edited by SiD (2007-11-20 21:32:36)

schivmeister · 2007-11-21 08:23:38

PHC is the best tool if power consumption is what you're concerned about

Those paths are same on all systems, well if not most. The pm-utils, speedstep & cpufrequtils wikis are good to read.

Nesa · 2007-11-21 08:39:25

another way would be :

 cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors 
       userspace ondemand conservative powersave performance             # output of my notebook

and then just set it to powersave. that would scale the cpu freq to the lowest that is awailable
or like Sid said set it to a specific frequency. But as far is i know u have to set the governor to userspace to specify a freq

Seb74 · 2007-11-21 10:08:41

I've never grasped this userspace-talk

Oh well, might give it a try, thanks. But first of all I'm gonna check what bios has to say.
So much to do, so little time

SiD · 2007-11-21 12:44:52

Nesa wrote:

But as far is i know u have to set the governor to userspace to specify a freq

Hmm, I set the governor to ondemand in /etc/rc.local and specifying a freq works.

this is my complete rc.local

#!/bin/bash
echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo 1400000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

Arch Linux

#1 2007-11-20 20:35:22

Lower the CPU frequency, permanently....how to do?

#2 2007-11-20 20:43:45

Re: Lower the CPU frequency, permanently....how to do?

#3 2007-11-20 20:47:39

Re: Lower the CPU frequency, permanently....how to do?

#4 2007-11-20 20:55:31

Re: Lower the CPU frequency, permanently....how to do?

#5 2007-11-20 20:56:01

Re: Lower the CPU frequency, permanently....how to do?

#6 2007-11-20 21:05:29

Re: Lower the CPU frequency, permanently....how to do?

#7 2007-11-20 21:30:44

Re: Lower the CPU frequency, permanently....how to do?

#8 2007-11-21 08:23:38

Re: Lower the CPU frequency, permanently....how to do?

#9 2007-11-21 08:39:25

Re: Lower the CPU frequency, permanently....how to do?

#10 2007-11-21 10:08:41

Re: Lower the CPU frequency, permanently....how to do?

#11 2007-11-21 12:44:52

Re: Lower the CPU frequency, permanently....how to do?

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