> 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
Note that the C++ standard deprecated monotonic_clock once they realized that there is absolutely no point in having a clock that jumps forward but not back, and that none of the operating systems implement such a thing -- instead they all implement a clock which doesn't jump in either direction. http://stackoverflow.com/questions/6777278/what-is-the-rationale-for-renaming-monotonic-clock-to-steady-clock-in-chrono In other words, yes! +1! The C++ standards folks just went through the process that we're now going through, and if we do it right we'll end up at the same place they are: http://en.cppreference.com/w/cpp/chrono/system_clock """ system_clock represents the system-wide real time wall clock. It may not be monotonic: on most systems, the system time can be adjusted at any moment. It is the only clock that has the ability to map its time points to C time, and, therefore, to be displayed. steady_clock: monotonic clock that will never be adjusted high_resolution_clock: the clock with the shortest tick period available """ Note that we don't really have the option of providing a clock which is "monotonic but not steady" in the sense of "can jump forward but not back". It is a misunderstanding (doubtless due to the confusing name "monotonic") to think that such a thing is offered by the underlying platforms. We can choose to *call* it "monotonic", following POSIX instead of calling it "steady", following C++. Regards, Zooko _______________________________________________ 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
