LinuxQuestions.org - How do I turn off my CPU Frequency Scaling?

I've got this script here, that I found on the net, that scales the core speeds to keep it at a temp that it was told to.

Code:

#!/bin/bash



# Usage: temp_throttle.sh max_temp

# USE CELSIUS TEMPERATURES.

# version 2.20



cat << EOF

Author: Sepero 2016 (sepero 111 @ gmx . com)

URL: http://github.com/Sepero/temp-throttle/

EOF



# Additional Links

# http://seperohacker.blogspot.com/2012/10/linux-keep-your-cpu-cool-with-frequency.html



# Additional Credits

# Wolfgang Ocker <weo AT weo1 DOT de> - Patch for unspecified cpu frequencies.



# License: GNU GPL 2.0



# Generic  function for printing an error and exiting.

err_exit () {

    echo ""

    echo "Error: $@" 1>&2

    exit 128

}



if [ $# -ne 1 ]; then

    # If temperature wasn't given, then print a message and exit.

    echo "Please supply a maximum desired temperature in Celsius." 1>&2

    echo "For example:  ${0} 60" 1>&2

    exit 2

else

    #Set the first argument as the maximum desired temperature.

    MAX_TEMP=$1

fi





### START Initialize Global variables.



# The frequency will increase when low temperature is reached.

LOW_TEMP=$((MAX_TEMP - 5))



CORES=$(nproc) # Get number of CPU cores.

echo -e "Number of CPU cores detected: $CORES\n"

CORES=$((CORES - 1)) # Subtract 1 from $CORES for easier counting later.



# Temperatures internally are calculated to the thousandth.

MAX_TEMP=${MAX_TEMP}000

LOW_TEMP=${LOW_TEMP}000



FREQ_FILE="/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies"

FREQ_MIN="/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq"

FREQ_MAX="/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq"



# Store available cpu frequencies in a space separated string FREQ_LIST.

if [ -f $FREQ_FILE ]; then

    # If $FREQ_FILE exists, get frequencies from it.

    FREQ_LIST=$(cat $FREQ_FILE) || err_exit "Could not read available cpu frequencies from file $FREQ_FILE"

elif [ -f $FREQ_MIN -a -f $FREQ_MAX ]; then

    # Else if $FREQ_MIN and $FREQ_MAX exist, generate a list of frequencies between them.

    FREQ_LIST=$(seq $(cat $FREQ_MAX) -100000 $(cat $FREQ_MIN)) || err_exit "Could not compute available cpu frequencies"

else

    err_exit "Could not determine available cpu frequencies"

fi



FREQ_LIST_LEN=$(echo $FREQ_LIST | wc -w)



# CURRENT_FREQ will save the index of the currently used frequency in FREQ_LIST.

CURRENT_FREQ=2



# This is a list of possible locations to read the current system temperature.

TEMPERATURE_FILES="

/sys/class/thermal/thermal_zone0/temp

/sys/class/thermal/thermal_zone1/temp

/sys/class/thermal/thermal_zone2/temp

/sys/class/hwmon/hwmon0/temp1_input

/sys/class/hwmon/hwmon1/temp1_input

/sys/class/hwmon/hwmon2/temp1_input

/sys/class/hwmon/hwmon0/device/temp1_input

/sys/class/hwmon/hwmon1/device/temp1_input

/sys/class/hwmon/hwmon2/device/temp1_input

null

"



# Store the first temperature location that exists in the variable TEMP_FILE.

# The location stored in $TEMP_FILE will be used for temperature readings.

for file in $TEMPERATURE_FILES; do

    TEMP_FILE=$file

    [ -f $TEMP_FILE ] && break

done



[ $TEMP_FILE == "null" ] && err_exit "The location for temperature reading was not found."





### END Initialize Global variables.





### START define script functions.



# Set the maximum frequency for all cpu cores.

set_freq () {

    # From the string FREQ_LIST, we choose the item at index CURRENT_FREQ.

    FREQ_TO_SET=$(echo $FREQ_LIST | cut -d " " -f $CURRENT_FREQ)

    echo $FREQ_TO_SET

    for i in $(seq 0 $CORES); do

        # Try to set core frequency by writing to /sys/devices.

        { sudo echo $FREQ_TO_SET 2> /dev/null > /sys/devices/system/cpu/cpu$i/cpufreq/scaling_max_freq; } ||

        # Else, try to set core frequency using command cpufreq-set.

        { sudo cpufreq-set -c $i --max $FREQ_TO_SET > /dev/null; } ||

        # Else, return error message.

        { err_exit "Failed to set frequency CPU core$i. Run script as Root user. Some systems may require to install the package cpufrequtils."; }

    done

}



# Will reduce the frequency of cpus if possible.

throttle () {

    if [ $CURRENT_FREQ -lt $FREQ_LIST_LEN ]; then

        CURRENT_FREQ=$((CURRENT_FREQ + 1))

        echo -n "throttle "

        set_freq $CURRENT_FREQ

    fi

}



# Will increase the frequency of cpus if possible.

unthrottle () {

    if [ $CURRENT_FREQ -ne 1 ]; then

        CURRENT_FREQ=$((CURRENT_FREQ - 1))

        echo -n "unthrottle "

        set_freq $CURRENT_FREQ

    fi

}



get_temp () {

    # Get the system temperature.



    TEMP=$(cat $TEMP_FILE)

}



### END define script functions.



echo "Initialize to max CPU frequency"

unthrottle





# Main loop

while true; do

    get_temp # Gets the current temperature and set it to the variable TEMP.

    if  [ $TEMP -gt $MAX_TEMP ]; then # Throttle if too hot.

        throttle

    elif [ $TEMP -le $LOW_TEMP ]; then # Unthrottle if cool.

        unthrottle

    fi

    sleep 3 # The amount of time between checking temperatures.

done

usage

Code:

./scriptName Max_temp

if you look at the code you can see how this is being done, so use it as is, or modify it, the thing to really check is the location of your cpu files that get edited. It is not a standard path naming scheme.

Code:

FREQ_FILE="/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies"

start with that then work your way backwards to see if the path matches, if it already doesn't. You'll see it in the script.