Ken Moffat wrote:
> On Sat, Jan 05, 2013 at 05:30:43PM -0500, Baho Utot wrote:
>>> As for cpu frequency, I think that mine is by default set to "ondemand"
>>> on this machine.
>> Just loading the module or building it into the kernel won't suffice.
>>
> Please note that I don't build the driver as a module. For my
> x86_64 machines I've always used ondemand and just set up a
> bootscript.
>
> The following is what I'm using for LFS-7.2. On a multiprocessor
> system it needs to be repeated for each cpu [ cpu0..3 in my case ].
>
> #!/bin/sh
>
> . /lib/lsb/init-functions
>
> case "${1}" in
> start|demand)
> log_info_msg "Enabling ondemand cpu frequency"
> echo ondemand
> >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
> evaluate_retval
> ;;
> powersave)
> log_info_msg "Enabling powersave cpu frequency"
> echo powersave
> >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
> evaluate_retval
> ;;
> performance)
> log_info_msg "Enabling performance cpu frequency"
> echo performance
> >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
> evaluate_retval
> ;;
> *)
> echo "Usage: ${0} {start|demand|powersave|performance}"
> exit 1
> ;;
> esac
>
> I wasn't intending show you my code to modify this after it has been
> copied in, because it is really ugly, but in the end it's easier to
> show it as one way which works to copy and alter the relevant lines.
> The debugging info is there in case it fails - only ever tested with
> 4 CPUs.
>
> # if more than 1 cpu, replicate for all of them - print debug info while it
> checks
> echo -n "searching to see if more than one cpu... "
> let EXTRACPUS=`cat /proc/cpuinfo | grep MHz | wc | awk '{ print --$1 }'`
> if [ $EXTRACPUS -gt 0 ]; then
> echo "yes"
> PREV=0
> THIS=1
> echo "entering loop for $EXTRACPUS pass(es), copying $PREV to $THIS"
> while [ $EXTRACPUS -gt 0 ]; do
> echo "adding cpufreq for processor $THIS"
> sed -i "/cpu$PREV/s/\(^.*\)$PREV\(.*$\)/\1$PREV\2\n\1$THIS\2/g"
> \
> /etc/rc.d/init.d/cpufreq
> # let returns zero for non-zero result and vice versa
> let PREV=$PREV+1
> let THIS=$THIS+1
> let EXTRACPUS=$EXTRACPUS-1
> echo "debug, after this pass values are $EXTRACPUS $PREV $THIS"
> done
> fi
>
> My old ppc64 was much more involved - had to load powernowd to be
> able to control the frequency.
>
> I'll also note that you can specify a default governor in the
> kernel.
>
> ĸen
In the kernel source code there is a app called cpupower that one just
needs to build. It can then be used as a user not root to set what
ever governor that you want. This could be included on the kernel build
page or made standalone. the cpupower app just requires cpupower
frequency-set -g <governor> and it sets for all cpu cores, you can also
change on the fly. One just needs the governor modules loaded or built
into the kernel for this to work.
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