Why is this simple python PIR motion sensor script using so much CPU power?

Question

I have a simple script I found that I'm using to deactivate xscreensaver via PIR motion sensor. It's using nearly 40% of my CPU when it runs. How can I calm it down?

#!/usr/bin/env python
import RPi.GPIO as GPIO
import os
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(17, GPIO.IN)
while True:
    if GPIO.input(17): # Waits for motion signal from PIR on GPIO pin 17 then complete rest and exit
        print ("deactivating screensaver")
        os.system("xscreensaver-command -deactivate")

Answer 1

Right now you are looping as fast as the CPU can process the loop. Try adding a sleep to back off the CPU. It is unlikely that you need to check the motion sensor as often as you are

#!/usr/bin/env python

import RPi.GPIO as GPIO
import os
import time

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(17, GPIO.IN)
while True:
    if GPIO.input(17): # Waits for motion signal from PIR on GPIO pin 17 then complete rest and exit
        print ("deactivating screensaver")
        os.system("xscreensaver-command -deactivate")
    time.sleep(1) # sleeps for 1 second