[Python-Dev] PEP 418: Add monotonic clock

[Victor Stinner]

> What is the utility of "strict=True"? If I wanted that mode of
> operation, then why would I not just try to use "time.monotonic()"
> directly?

I mentioned the strict=True API in the PEP just to list all
propositions, but the PEP only proposes time.monotonic() and
time.try_monotonic(), no the flags API.

> At worst, it generates an "AttributeError" (although that is not clear from your PEP).

I tried to mention when a function is always available or not always
available. Is it better in the last version of the PEP?

>  system_clock = wall clock time
>  monotonic_clock = always goes forward but can be adjusted
>  steady_clock = always goes forward and cannot be adjusted
>  high_resolution_clock = steady_clock || system_clock

I tried to follow these names in the PEP. I don't propose steady_clock
because I don't see exactly which clocks would be used to implement
it, nor if we need to provide monotonic *and* steady clocks. What do
you think?

> Straying from that is only going to create confusion. Besides that, the
> one use case for "time.steady()" that you give (benchmarking) is better
> served by a clock that follows the C++0x definition.

I added a time.hires() clock to the PEP for the benchmarking/profiling
use case. This function is not always available and so a program has
to fallback manually to another clock. I don't think that it is an
issue: Python programs already have to choose between time.clock() and
time.time() depending on the OS (e.g. timeit module and pybench
program).

> As well, certain
> kinds of scheduling/timeouts would be better implemented with the C++0x
> definition for "steady" rather than the "monotonic" one and vice-versa.

Sorry, I don't understand. Which kind of scheduling/timeouts?

The PEP is still a draft (work-in-progress).

Victor