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[Python-Dev] PEP 410 (Decimal timestamp): the implementation is ready for a review

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On Wed, 15 Feb 2012 20:56:26 +0100"Martin v. Löwis" <martin at v.loewis.de> wrote:>> With the quartz in Victor's machine, a single clock takes 0.3ns, so> three of them make a nanosecond. As the quartz may not be entirely> accurate (and also as the CPU frequency may change) you have to measure> the clock rate against an external time source, but Linux has> implemented algorithms for that. On my system, dmesg shows>> [    2.236894] Refined TSC clocksource calibration: 2793.000 MHz.> [    2.236900] Switching to clocksource tscBut that's still not meaningful. By the time clock_gettime() returns,an unpredictable number of nanoseconds have elapsed, and even more whenreturning to the Python evaluation loop.So the nanosecond precision is just an illusion, and a float shouldreally be enough to represent durations for any task where Python issuitable as a language.RegardsAntoine.

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