Post by Henrik CarlqvistPowertop says the system is using about 15W on battery giving about 3.5
hours batt life, not bad for a 5-year old battery. I might be able to
tune power down a little.
cat /usr/local/etc/rc.d/rc.cpufreq
#!/bin/sh
# Fix cpu frequency adaption to load
/sbin/modprobe acpi-cpufreq 2>/dev/null && \
/sbin/modprobe cpufreq_ondemand && \
find /sys/devices/system/cpu -name scaling_governor -exec \
sh -c 'echo ondemand > {}' \; && \
echo CPU frequency will be adapted to load || \
echo No CPU frequency adaption on this machine...
echo 1 > /sys/devices/system/cpujk/cpufreq/ondemand/ignore_nice_load
echo 100 > /sys/devices/system/cpu/cpufreq/ondemand/sampling_down_factor
echo 50 > /sys/devices/system/cpu/cpufreq/ondemand/up_threshold
The above script is not specific for laptops, I also use it for desktops
and servers. Without load or only nice loads cores will run at minimum
supported frequencies and when working the frequencies (and power
consumption) will be maximized. It is easy to check that the settings
cat /proc/cpuinfo | grep MHz
cpu MHz : 800.000
cpu MHz : 800.000
cpu MHz : 1200.000
cpu MHz : 3801.000
cpu MHz : 800.000
cpu MHz : 3801.000
cpu MHz : 800.000
cpu MHz : 800.000
regards Henrik
Hi Henrik, thanks for your script. It appears that slackware-current is
already setup to use the ondemand scaling governor (at least, in the
recent image that I downloaded!), however I found the
sampling_down_threshold is set to 1 (instead of your value of 100) and
the up_threshold is set to 95 (instead of 50) by default. I have tried
running some loads and watching the cpu frequencies reported by
/proc/cpuinfo, and they correctly scale up to the max under load and
drop back down when idle; and each core is scaled individually.
So it would appear that slackware-current has implemented something
similar to your script by default.