So using floats we can match 100ns precision, right? On Wed, Feb 15, 2012 at 9:58 AM, 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? > > Test the following C program: > ------------ > #include <stdio.h> > #include <time.h> > > int main(int argc, char **argv, char **arge) { > struct timespec tps, tpe; > if ((clock_gettime(CLOCK_REALTIME, &tps) != 0) > || (clock_gettime(CLOCK_REALTIME, &tpe) != 0)) { > perror("clock_gettime"); > return -1; > } > printf("%lu s, %lu ns\n", tpe.tv_sec-tps.tv_sec, > tpe.tv_nsec-tps.tv_nsec); > return 0; > } > ------------ > Compile it using gcc time.c -o time -lrt. > > It gives me differences smaller than 1000 ns on Ubuntu 11.10 and a > Intel Core i5 @ 3.33GHz: > > $ ./a.out > 0 s, 781 ns > $ ./a.out > 0 s, 785 ns > $ ./a.out > 0 s, 798 ns > $ ./a.out > 0 s, 818 ns > $ ./a.out > 0 s, 270 ns > > Victor > _______________________________________________ > 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/guido%40python.org
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