See README for description

README

For Android devices: Script for setting CPU Scaling parameters (governor, min_freq, max_freq)
for all CPU cores.

Doesn't work for all devices - e.g. for my SGS4 the max_freq for additional cores (core != 0)
gets reset to the nominal CPU maximum frequency (cpuinfo_max_freq) when the cpu reawakens from
sleep state. So I'm leaving this here only for educational purposes and future reference for
myself.

This was tested on CyanogenMod 12.1. It should in theory work (as in the script should execute
without errors) on any rooted device with busybox installed.

The script also has the CPU cores to set the parameters on hardcoded (on the SGS4, 4 cores). Set
the cpusToApply array accordingly.

setCpuScaling.sh

#!/system/bin/sh

if [[ $# -ne 3 ]]; then
	echo "Arguments missing! Usage: $0 <governor> <min_freq> <max_freq>"
	exit 1;
fi

cpusToApply=(0 1 2 3)

isCpuOnApplyQueue() {
	for c in "${cpusToApply[@]}"; do [[ $c -eq $1 ]] && echo 1 && return; done
	echo 0
}

popCpuFromApplyQueue() {
	local arrCount
	local modifiedArray
	arrCount=$((${#cpusToApply[@]} - 1))
	modifiedArray=()
	for i in `seq 0 ${arrCount}`; do [[ ${cpusToApply[$i]} -ne $1 ]] && modifiedArray+=(${cpusToApply[$i]}); done
	echo ${modifiedArray[@]}
}

while [ ${#cpusToApply[@]} -gt 0 ]; do
	for p in "${cpusToApply[@]}"; do
		echo "1" > /sys/devices/system/cpu/cpu$p/online
		echo $1 2> /dev/null > /sys/devices/system/cpu/cpu$p/cpufreq/scaling_governor
		echo $2 2> /dev/null > /sys/devices/system/cpu/cpu$p/cpufreq/scaling_min_freq
		echo $3 2> /dev/null > /sys/devices/system/cpu/cpu$p/cpufreq/scaling_max_freq
		
		govState=$(cat /sys/devices/system/cpu/cpu$p/cpufreq/scaling_governor 2> /dev/null)
		minFreq=$(cat /sys/devices/system/cpu/cpu$p/cpufreq/scaling_min_freq 2> /dev/null)
		maxFreq=$(cat /sys/devices/system/cpu/cpu$p/cpufreq/scaling_max_freq 2> /dev/null)
		
		if [[ "$govState" = "$1" && "$minFreq" = "$2" && "$maxFreq" = "$3" ]]; then
			cpusToApply=(`popCpuFromApplyQueue ${p}`)
			echo "Scaling set done on CPU $p"
		fi
	done
done