changes CPU Freq based on cpu temp 😎

#!/usr/bin/env bash

LOCKFILE=/tmp/thermal_governor.lock

# Try to acquire exclusive lock, fail if locked
exec 200>"$LOCKFILE"
flock -n 200 || { echo "Another instance is already running. Exiting."; exit 1; }

# Configurable limits
MIN_FREQ_MHZ=800
MAX_FREQ_MHZ=3700
STEP_SMALL=50
STEP_MED=100
STEP_LARGE=800
INTERVAL=7  # seconds between checks

# Helper: Set CPU frequency
set_freq() {
    local freq="$1"
    sudo cpupower frequency-set -u "${freq}MHz" -d "${freq}MHz" > /dev/null
    echo "Set CPU frequency to ${freq}MHz"
}

# Helper: Read CPU temp in °C
read_temp() {
    sensors 2>/dev/null | awk '/Package id 0:/ {gsub(/\+|°C/, "", $4); print int($4)}' | head -n1
}

# Helper: Get current CPU frequency (MHz, rounded down)
get_current_freq() {
    awk '/cpu MHz/ {printf "%.0f\n", $4; exit}' /proc/cpuinfo
}

# Initialize
echo "Starting thermal governor with range ${MIN_FREQ_MHZ}-${MAX_FREQ_MHZ} MHz"
current_freq=$(get_current_freq)
prev_freq=$current_freq
set_freq "$current_freq"

# Loop
while true; do
    temp=$(read_temp)

    if [[ -z "$temp" ]]; then
        echo "Could not read temperature. Retrying in 1s."
        sleep 1
        continue
    fi

    echo "Temp: ${temp}°C | Current freq: ${current_freq}MHz"

    if (( temp >= 59 )); then
        (( current_freq -= STEP_LARGE ))
        echo "Temp ≥ 59°C → Dropping by ${STEP_LARGE}MHz"
    elif (( temp >= 55 )); then
        (( current_freq -= STEP_MED ))
        echo "Temp >= 55°C → Dropping by ${STEP_MED}MHz"
    elif (( temp >= 51 )); then
        (( current_freq -= STEP_SMALL ))
        echo "Temp > 51°C → Dropping by ${STEP_SMALL}MHz"
    elif (( temp < 46 )); then
        (( current_freq += STEP_SMALL ))
        echo "Temp < 46°C → Raising by ${STEP_SMALL}MHz"
    else
        echo "Temp stable (46–51°C). No change."
    fi

    # Clamp frequency to safe bounds
    if (( current_freq < MIN_FREQ_MHZ )); then current_freq=$MIN_FREQ_MHZ; fi
    if (( current_freq > MAX_FREQ_MHZ )); then current_freq=$MAX_FREQ_MHZ; fi

    # Only set frequency if it changed
    if (( current_freq != prev_freq )); then
        set_freq "$current_freq"
        prev_freq=$current_freq
    else
        echo "Frequency unchanged at ${current_freq}MHz. No command sent."
    fi

    sleep "$INTERVAL"
done