time.monotonic()

time.monotonic()

Return the value (in fractional seconds) of a monotonic clock, i.e. a clock that cannot go backwards. The clock is not affected by system clock updates. The reference point of the returned value is undefined, so that only the difference between the results of consecutive calls is valid.

On Windows versions older than Vista, monotonic() detects GetTickCount() integer overflow (32 bits, roll-over after 49.7 days). It increases an internal epoch (reference time) by 2³² each time that an overflow is detected. The epoch is stored in the process-local state and so the value of monotonic() may be different in two Python processes running for more than 49 days. On more recent versions of Windows and on other operating systems, monotonic() is system-wide.