On Wed, Feb 15, 2012 at 6:06 PM, Greg Ewing <greg.ew...@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 it matters. Read the rest of the thread. -- --Guido van Rossum (python.org/~guido) _______________________________________________ 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
