The original RFE at issue 7989 was:

"""
After discussion on numerous issues, python-dev, and here at the PyCon sprints, it seems to be a good idea to move timemodule.c to _timemodule.c and convert as much as possible into pure Python. The same change seems good for datetime.c as well.
"""

See msg99774.  I have changed issue 7989 to cover datetime only because I argued that as a thin wrapper around C library calls, this module is an exception to the general rule that pure python implementations are a good idea.  See msg107303.

No I realize that in order to break circular dependency between time and datetime modules, it will be helpful to create an _time module that would provide lower than time module access to system facilities and datetime and time modules would be use _time module to implement higher level interfaces either in C or in Python.

I believe _time module should become the home of the gettimeofday() method and pure python implementation of time.time() will be

def time()
   s, us = _time.gettimeofday()
   return s + 1e-6 * us


Similarly time.sleep() can be implemented in terms of lower level POSIX nanosleep() method.

Lower level localtime() function can provide access to tm_zone and tm_gmtoff members of struct tm (where available) without concerns about backward compatibility.