Script to adjust cpu frequency according to cpu temprature

[Cem Kayali <cemkayali%eticaret.com.tr@localhost>]

Hi,

I have searched through Google and maling lists, and couldn't find a 
good script that adjusts cpu frequency with respect to cpu temperature 
(there are different approaches as far as i see).

This is very important for notebooks, and generally cooling problem 
arises once a script (especially compiling process) uses cpus for along 
time. In other words, this small script helps your notebook to live 
longer (hopefully).


How to use:

1- According to number of cpus, add/remove temp{0} lines. Below one is 
for core duo cpu and it checks temperature of both core. I would first 
test value of 'envstat | grep cpu0 | cut -d \  -f 9 | cut -b 1,2' 
command to make sure it gives the temperature of the core 0.

2- Check your supported frequncies by 'sysctl -a | grep 
machdep.est.frequency.available' command...

3- Add/remove and adjust elif/then sections according to your cpu 
frequncies supported and desired temperature levels. Below one ie; 
reduces frequency to 1400 MHz once temperature is higher than 60 C 
degree and below 65 C degree.

4- Create a crontab and run the script every ie; 5 mins.


#######################################
#!/bin/sh

temp0=`envstat | grep cpu0 | cut -d \  -f 9 | cut -b 1,2`
temp1=`envstat | grep cpu1 | cut -d \  -f 9 | cut -b 1,2`

 if [ ${temp0} -gt 65 ] || [ ${temp1} -gt 65 ];
then sysctl -w machdep.est.frequency.target=1200

elif [ ${temp0} -gt 60 ] || [ ${temp1} -gt 60 ];
then sysctl -w machdep.est.frequency.target=1400

elif [ ${temp0} -gt 55 ] || [ ${temp1} -gt 55 ];
then sysctl -w machdep.est.frequency.target=1600

elif [ ${temp0} -gt 50 ] || [ ${temp1} -gt 50 ];
then sysctl -w machdep.est.frequency.target=1800

elif [ ${temp0} -gt 45 ] || [ ${temp1} -gt 45 ];
then sysctl -w machdep.est.frequency.target=2000

elif [ ${temp0} -gt 40 ] || [ ${temp1} -gt 40 ];
then sysctl -w machdep.est.frequency.target=2200

else
fi
#######################################


Use at your own risk of course.


Best regards,
Cem