Equivalent to GetTickCount() on Linux

Question

I'm looking for an equivalent to GetTickCount() on Linux.

Presently I am using Python's time.time() which presumably calls through to gettimeofday(). My concern is that the time returned (the unix epoch), may change erratically if the clock is messed with, such as by NTP. A simple process or system wall time, that only increases positively at a constant rate would suffice.

Does any such time function in C or Python exist?

Answer 1

Yes, the kernel has high-resolution timers but it is differently. I would recommend that you look at the sources of any odd project that wraps this in a portable manner.

From C/C++ I usually #ifdef this and use gettimeofday() on Linux which gives me microsecond resolution. I often add this as a fraction to the seconds since epoch I also receive giving me a double.

Answer 2

You can use CLOCK_MONOTONIC e.g. in C:

struct timespec ts;
if(clock_gettime(CLOCK_MONOTONIC,&ts) != 0) {
 //error
}

See this question for a Python way - http://stackoverflow.com/questions/1205722/how-do-i-get-monotonic-time-durations-in-python

Answer 3

You should use: clock_gettime(CLOCK_MONOTONIC, &tp);. This call is not affected by the adjustment of the system time just like GetTickCount() on Windows.