On 13 Mar 2012, at 16:57, Victor Stinner wrote: > Hi, > > I added two functions to the time module in Python 3.3: wallclock() > and monotonic(). I'm unable to explain the difference between these > two functions, even if I wrote them :-) wallclock() is suppose to be > more accurate than time() but has an unspecified starting point. > monotonic() is similar except that it is monotonic: it cannot go > backward. monotonic() may not be available or fail whereas wallclock() > is available/work, but I think that the two functions are redundant. > > I prefer to keep only monotonic() because it is not affected by system > clock update and should help to fix issues on NTP update in functions > implementing a timeout. > > What do you think? >
I am in the middle of adding a feature to unittest that involves timing of individual tests. I want the highest resolution cross platform measure of wallclock time - and time.wallclock() looked ideal. If monotonic may not exist or can fail why would that be better? Michael > -- > > monotonic() has 3 implementations: > * Windows: QueryPerformanceCounter() with QueryPerformanceFrequency() > * Mac OS X: mach_absolute_time() with mach_timebase_info() > * UNIX: clock_gettime(CLOCK_MONOTONIC_RAW) or clock_gettime(CLOCK_MONOTONIC) > > wallclock() has 3 implementations: > * Windows: QueryPerformanceCounter() with QueryPerformanceFrequency(), > with a fallback to GetSystemTimeAsFileTime() if > QueryPerformanceFrequency() failed > * UNIX: clock_gettime(CLOCK_MONOTONIC_RAW), > clock_gettime(CLOCK_MONOTONIC) or clock_gettime(CLOCK_REALTIME), with > a fallback to gettimeofday() if clock_gettime(*) failed > * Otherwise: gettimeofday() > > (wallclock should also use mach_absolute_time() on Mac OS X) > > > Victor > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/fuzzyman%40voidspace.org.uk > -- http://www.voidspace.org.uk/ May you do good and not evil May you find forgiveness for yourself and forgive others May you share freely, never taking more than you give. -- the sqlite blessing http://www.sqlite.org/different.html _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
