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

Victor Stinner victor.stinner at gmail.com
Wed Feb 15 18:58:54 CET 2012

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

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