How to measure time up to millisecond in Cython?

Question

I have read this question, but I would like to get better timing precision than a second: is this possible with some function of libc?

This is to use inside with nogil, so of course no Python is allowed...

Answer 1

You can use POSIX clock_gettime():

from posix.time cimport clock_gettime, timespec, CLOCK_REALTIME

cdef timespec ts
cdef double current
clock_gettime(CLOCK_REALTIME, &ts)
current = ts.tv_sec + (ts.tv_nsec / 1000000000.)

This snippet store in current the number of seconds since epoch with up to a nanosecond precision (depending on your system).

You can also use gettimeofday(), but it is now deprecated:

POSIX.1-2008 marks gettimeofday() as obsolete, recommending the use of clock_gettime(2) instead.