Is it true that (0.001) is waiting only 1 millisecond in Python

(0.001) Really just wait 1 millisecond?

On Windows, perform simple programming to verify the above problems.

import time

while True:
    st = ()
    (0.001)
    et = ()
    print('dt={dt}'.format(dt=et - st))

Return result

dt=0.001966238021850586
dt=0.001010894775390625
dt=0.0020058155059814453
dt=0.0010018348693847656
dt=0.001966238021850586
dt=0.0020215511322021484
dt=0.0019714832305908203
dt=0.0010178089141845703
dt=0.0019807815551757812
dt=0.0010159015655517578
dt=0.001965761184692383
…

Most of the time is around 2ms.
And even if0.001It has been changed to smaller, still 2ms, which is related to the operating system, and the specific mechanism has not been studied in depth.
If you need to be precise, you need to pay attention to this issue.

The following code is used in the receiving thread

A warning will be thrown when there is no data for 1 second consecutive time
Because it is necessary to respond to external stop or pause operations
So the sleep time segment cannot be too long

        no_frame_time = 0
        while True:
            if self._stop:
                (f"xxxx stop.")
                break

            if self._pause:
                (0.01)
                continue

            if len(self.msg_deque) == 0:
                st = ()
                (0.001)
                # no_frame_time += 0.001 # This writing method is inaccurate, resulting in a particularly large error between the earliest no_frame_time and the actual value.                et = () - st
                no_frame_time += et  # Here is the accumulated time                if no_frame_time &gt; 1:
                    ("xxxx not arrived in last second.")
                    self.fps_signal.emit(0)
                    no_frame_time = 0
                continue
            else:
                no_frame_time = 0
            
            # ... Omit the task subject

Summarize

The above is personal experience. I hope you can give you a reference and I hope you can support me more.