A bad way to time threaded infinite loops

threaded_loop_timing_bad.py

def run(self):
    while True:
        before_ts = time_ns()
        for num in range(0, 1000):
            print(num)
        after_ts = time_ns()
        print('loop time: ' + str(after_ts - before_ts))
        sleep(1)
        print('loop complete')