On Wed, 15 Feb 2012 18:23:55 +0100 Victor Stinner <victor.stin...@gmail.com> wrote: > > Linux supports nanosecond timestamps since Linux 2.6, Windows supports > 100 ns resolution since Windows 2000 or maybe before. It doesn't mean > that Windows system clock is accurate: in practical, it's hard to get > something better than 1 ms :-)
Well, do you think the Linux system clock is nanosecond-accurate? A nanosecond is what it takes to execute a couple of CPU instructions. Even on a real-time operating system, your nanosecond-precise measurement is already obsolete when it starts being processed by the higher-level application. A single cache miss in the CPU will make the precision worthless. And in a higher-level language like Python, the execution times of individual instructions are not specified or stable, so the resolution brings you nothing. > "Improved timestamps > As computers become faster in general and as Linux becomes used > more for mission-critical applications, the granularity of > second-based timestamps becomes insufficient. To solve this, ext4 > provides timestamps measured in nanoseconds. (...)" This is a fallacy. Just because ext4 is able to *store* nanoseconds timestamps doesn't mean the timestamps are accurate up to that point. > Such test is common in build programs like make or scons. scons is written in Python and its authors have not complained, AFAIK, about timestamp precision. Regards Antoine. _______________________________________________ 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
