Sleep for exact time in python

Question

I need to wait for about 25ms in one of my functions. Sometimes this function is called when the processor is occupied with other things and other times it has the processor

Answer 1

Another solution for accurate timings and delay is to use the perf_counter() function from module time. Especially useful in windows as time.sleep is not accurate in milliseconds. See below example where function accurate_delay creates a delay in millisecond.

import time


def accurate_delay(delay):
    ''' Function to provide accurate time delay in millisecond
    '''
    _ = time.perf_counter() + delay/1000
    while time.perf_counter() < _:
        pass


delay = 10
t_start = time.perf_counter()
print('Wait for {:.0f} ms. Start: {:.5f}'.format(delay, t_start))

accurate_delay(delay)

t_end = time.perf_counter()
print('End time: {:.5f}. Delay is {:.5f} ms'.
      format(t_end, 1000*(t_end - t_start)))

sum = 0
ntests = 1000
for _ in range(ntests):
    t_start = time.perf_counter()
    accurate_delay(delay)
    t_end = time.perf_counter()
    print('Test completed: {:.2f}%'.format(_/ntests * 100), end='\r', flush=True)
    sum = sum + 1000*(t_end - t_start) - delay

print('Average difference in time delay is {:.5f} ms.'.format(sum/ntests))