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[Python-Dev] PEP 410 (Decimal timestamp): the implementation is ready for a review
Guido van Rossumguido at python.org
Thu Feb 16 03:39:18 CET 2012
On Wed, Feb 15, 2012 at 6:06 PM, Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:> On 16/02/12 06:43, Guido van Rossum wrote:>>>> This does not explain why microseconds aren't good enough. It seems>> none of the clocks involved can actually measure even relative time>> intervals more accurate than 100ns, and I expect that kernels don't>> actually keep their clock more accurate than milliseconds.>>> I gather that modern x86 CPUs have a counter that keeps track of> time down to a nanosecond or so by counting clock cycles. In> principle it seems like a kernel should be able to make use of> it in conjunction with other timekeeping hardware to produce> nanosecond-resolution timestamps.>> Whether any existing kernel actually does that is another> matter. It probably isn't worth the bother for things like> file timestamps, where the time taken to execute the system> call that modifies the file is likely to be several orders> of magnitude larger.Ironically, file timestamps are likely the only place where itmatters. Read the rest of the thread.-- --Guido van Rossum (python.org/~guido)
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