On Tue, Mar 27, 2012 at 7:03 PM, Lennart Regebro <rege...@gmail.com> wrote: > But a time.steady() that tries to get a "best case" doesn't make sense > at this time, as apparently nobody knows what a best case is, or what > it should be called, except that it should apparently not be called > steady(). Since monotonic() raises an error if there is no monotonic > clock available, implementing your own fallback is trivial in any > case.
+1 from me to Lennart's suggestion of mostly just exposing time.monotonic() without trying to get too clever. Applications that need a truly precise time source should *never* be reading it from the host OS (one fairly good solution can be to read your time directly from an attached GPS device). However, I think Victor's right to point out that the *standard library* needs to have a fallback to maintain backwards compatibility if time.monotonic() isn't available, and it seems silly to implement the same fallback logic in every module where we manipulate timeouts. As I concur with others that time.steady() is a thoroughly misleading name for this concept, I suggest we encapsulate the "time.monotic if available, time.time otherwise" handling as a "time.try_monotic()" function. That's simple clear and explicit: try_monotic() tries to use the monotic clock if it can, but falls back to time.time() rather than failing entirely if no monotonic clock is available. This is essential for backwards compatibility when migrating any current use of time.time() over to time.monotic(). Yes the monotonic clock is *better* for many use cases (including timeouts), but you'll usually be OK with the non-monotonic clock, too (particularly if that's what you were using anyway in earlier versions). After all, we've survived this long using time.time() for our timeout calculations, and bugs associated with clock adjustments are a rather rare occurrence. Third party libraries that need to support earlier Python versions can then implementation their own fallback logic (since they couldn't rely on time.try_monotonic being available either). The 3.3 time module would then be left with three interfaces: time.time() # Highest resolution timer available time.monotonic() # I'm not yet convinced we need the "raw" parameter but don't much mind either way time.try_monotonic() # Monotonic is preferred, but non-monotonic presents a tolerable risk Regards, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia _______________________________________________ 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
