python process takes 100% CPU

Question

I am trying to run python application and execute actions based on specified interval. Below code is consuming constantly 100% of CPU.

def action_print():

    p         


        

Answer 1

If you know when the next run will be, you can simply use time.sleep:

import time
interval = 5
next_run = 0
while True:
   time.sleep(max(0, next_run - time.time()))

   next_run = time.time() + interval
   action_print()

If you want other threads to be able to interrupt you, use an event like this:

import time,threading
interval = 5
next_run = 0
interruptEvent = threading.Event()
while True:
   interruptEvent.wait(max(0, next_run - time.time()))
   interruptEvent.clear()

   next_run = time.time() + interval
   action_print()

Another thread can now call interruptEvent.set() to wake up yours.

In many cases, you will also want to use a Lock to avoid race conditions on shared data. Make sure to clear the event while you hold the lock.

You should also be aware that under cpython, only one thread can execute Python code. Therefore, if your program is CPU-bound over multiple threads and you're using cpython or pypy, you should substitute threading with multiprocessing.