[mythtv-users] Cool'n'Quiet setup help

John Finlay finlay at moeraki.com
Mon Feb 9 09:35:43 UTC 2009


Allen Edwards wrote:
>
>
> On Mon, Feb 9, 2009 at 12:44 AM, John Finlay <finlay at moeraki.com 
> <mailto:finlay at moeraki.com>> wrote:
>
>     Allen Edwards wrote:
>
>
>
>         On Sun, Feb 8, 2009 at 5:03 PM, John Finlay
>         <finlay at moeraki.com <mailto:finlay at moeraki.com>
>         <mailto:finlay at moeraki.com <mailto:finlay at moeraki.com>>> wrote:
>
>            Allen Edwards wrote:
>
>                I have an AMD 5400+ running Mythbuntu 8.10.  I would
>         like to
>                run cool'n'quiet to cut the cpu temp and power.  I
>         enabled it
>                in the BIOS and the results were unsatisfactory.  The
>         program
>                would stutter.  I could see that the cpu was running at
>         1GHz
>                during program mode and that wasn't enough.
>
>                What I want to do is have the CPU at a low clock
>         frequency but
>                when there is basically any activity at all, have it go to
>                100% clock.  For example, right now the CPU is at .6%.  It
>                would be nice if the clock was at a minimum.  But if
>         the cpu
>                goes above, say 2%?, I want the CPU to go to max clock
>         so it
>                wont stutter.
>
>                I see instructions on the net how to do this but they are 3
>                years old and experience has thought me that following
>                instructions like this causes a half day work getting the
>                system working again because the instructions were for an
>                older system.
>
>                So, can anyone with a system like mine who has enabled
>                cool'n'quiet and understands what I am saying help me out?
>
>                Allen
>
>            This uses the cpufreq module which uses the threshold (%
>         cpu) in:
>
>            /sys/devices/system/cpu/cpu0/cpufreq/ondemand/up_threshold
>
>            As root you can change this e.g.:
>
>            echo -n 10 >
>            /sys/devices/system/cpu/cpu0/cpufreq/ondemand/up_threshold
>
>            Other params in /sys/devices/system/cpu/cpu0/cpufreq can be
>            changed as well:
>
>            scaling_max_freq
>            scaling_min_freq
>            ondemand/ignore_nice_load
>
>            If using Ubuntu you can set params on boot in the
>            /etc/init.d/powernowd file. Add in the use_ondemand() function
>            something like:
>
>                      if [ -f $x"cpufreq/ondemand/up_threshold" ]; then
>                          echo -n 20 > $x"cpufreq/ondemand/up_threshold"
>                      fi
>
>
>            If using Fedora the /etc/sysconfig/cpuspeed file allows you to
>            tweak things.
>
>            John
>
>
>         I apologize if this is a stupid question but I don't have a
>         file called up_threshold on my system.  I do have powernowd
>         but not cpufreq.  I can find online docs for powernowd  but
>         again they are many years old and I have to assume out of date.
>
>         Allen
>
>
>     Sounds like you are not loading the kernel module that provides
>     cpufreq.
>
>     Install the powernowd package if it isn't already there (I think
>     it's there by default). On my systems the powernowd rc links load
>     the required modules but don't start the powernowd daemon. Check
>     to see that both the powernod and powernod.early rc links are setup.
>
>     Here's the way to do it without the powernowd package:
>
>     http://ubuntuforums.org/showthread.php?t=248867)
>
>     A quick test is to:
>
>     lsmod | grep powernow-k8
>     lsmod|grep cpufreq
>
>     to check if the modules are loaded. If not you can :
>
>     modprobe powernow-k8
>     modprobe cpufreq_ondemand
>
>     to load them. Then the /sys/devices/system/cpu/cpu0/cpufreq
>     directory should exist.
>
>     John
>
>
>
> Here is what I got (although cool'n'quiet is not presently enabled in 
> the bios if that makes a difference):
>
> dad at myth_desktop:~$ lsmod | grep powernow-k8
> dad at myth_desktop:~$ lsmod|grep cpufreq
> cpufreq_ondemand        9740  0
> cpufreq_conservative     8712  0
> cpufreq_stats           7104  0
> freq_table              5536  2 cpufreq_ondemand,cpufreq_stats
> cpufreq_powersave       2688  0
> cpufreq_userspace       5284  0
> dad at myth_desktop:~$
>
> As far as what is loaded, it is stock Mythbuntu so whatever gets 
> loaded with that is what I have.
>
> cool'n'quiet works when I enable it in the bios.  I just don't like 
> the set points and it doesn't seem to be ondemand in that there are 3 
> levels of frequency selected vs cpu load.  Does that fact give a clue 
> as to what my correct setup should be?
>
> Allen
>
>
You need to have C&Q enabled in the BIOS. Then cd to the 
/sys/devices/system/cpu/cpu0/cpufreq directory and cat the 
scaling_governor - it should be ondemand. The levels available are listed by

cat scaling_available_frequencies

John


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