[Python-Dev] PEP 418: Add monotonic clock

[Victor Stinner]

> I started to write the PEP 418 to clarify the notions of monotonic and
> steady clocks.

I replaced time.steady() by time.try_monotonic(). I misunderstood "may
not" in the C++ doc: I understood it as "it may be adjusted by NTP",
whereas it means "it cannot be adjusted". Sorry for the confusion.

I added a time.hires() clock because time.monotonic() and
time.try_monotonic() are not the best clocks for profiling or
benchmarking. For example, on Windows, time.hires() uses
QueryPerformanceCounter() whereas time.monotonic() and
time.try_monotonic() uses GetTickCount[64]().

I added the pseudo-code of each function. I hope that it is easier to
understand than a long text.

Victor