[New-bugs-announce] [issue31803] Remove not portable time.clock(), replaced by time.perf_counter() and time.process_time()

[STINNER Victor]

New submission from STINNER Victor <victor.stinner at gmail.com>:

The behaviour of the time.clock() function is not portable: on Windows it mesures wall-clock, whereas it measures CPU time on Unix. Python has time.process_time() and time.perf_counter(), since Python 3.3, which are portable, well defined and have a better resolution.

time.clock() was deprecated in Python 3.3 documentation, but calling time.clock() didn't raise a DeprecationWarning. I proposed to remove it from Python 3.7.

Sometimes, a deprecated function raises a DeprecationWarning in Python version N, before removing it from Python version N. time.clock() doesn't emit such warning, but I consider that it is possible to remove it anyway.

While it can be annoying to have to patch code to no more use time.clock(), I consider that it's worth it for portability and better clock resolution.

Attached PR removes time.clock() and time.get_clock_info() doens't accept 'clock' anymore.

Current time.clock() documentation:
----------------------------
.. function:: clock()

   .. index::
      single: CPU time
      single: processor time
      single: benchmarking

   On Unix, return the current processor time as a floating point number expressed
   in seconds.  The precision, and in fact the very definition of the meaning of
   "processor time", depends on that of the C function of the same name.

   On Windows, this function returns wall-clock seconds elapsed since the first
   call to this function, as a floating point number, based on the Win32 function
   :c:func:`QueryPerformanceCounter`. The resolution is typically better than one
   microsecond.

   .. deprecated:: 3.3
      The behaviour of this function depends on the platform: use
      :func:`perf_counter` or :func:`process_time` instead, depending on your
      requirements, to have a well defined behaviour.
----------------------------

----------
components: Library (Lib)
messages: 304502
nosy: haypo
priority: normal
severity: normal
status: open
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue31803>
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