Measure performance for different time functions

time_perf.c

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <time.h>
#include <sys/time.h>

/*
Build:
gcc -o time_perf time_perf.c

Run:
./time_perf 10000000

Reference results (Intel Pentium N3700):
time() in 0.182687 sec
clock() in 3.756838 sec
timespec_get() in 0.717233 sec
gettimeofday() in 0.529567 sec
clock_gettime(REALTIME) in 0.708866 sec
clock_gettime(MONOTONIC) in 0.704702 sec
clock_gettime(REALTIME_COARSE) in 0.458660 sec
clock_gettime(MONOTONIC_COARSE) in 0.479514 sec
clock_gettime(MONOTONIC_RAW) in 1.943516 sec
clock_gettime(PROCESS_CPUTIME) in 3.621124 sec
clock_gettime(THREAD_CPUTIME) in 3.527629 sec

*/

void usage()
{
	printf(
"USAGE:\n"
"	time_perf <count>\n\n"
"\n"
);
}

int main(int argc, char* argv[])
{
	clock_t start;
	clock_t c;
	struct timespec ts;
	struct timeval tv;
	time_t t;

	if(argc < 2) {
		usage();
		return 1;
	}
	int count = atoi(argv[1]);

	start = clock();
	for(int i = 0; i < count; i++)
		t = time(NULL);

	printf("time() in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

        start = clock();
        for(int i = 0; i < count; i++)
                c = clock();

        printf("clock() in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

        start = clock();
        for(int i = 0; i < count; i++)
                c = timespec_get(&ts, TIME_UTC);

        printf("timespec_get() in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

        start = clock();
        for(int i = 0; i < count; i++)
                gettimeofday(&tv, NULL);

        printf("gettimeofday() in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

        start = clock();
        for(int i = 0; i < count; i++)
                clock_gettime(CLOCK_REALTIME, &ts);

        printf("clock_gettime(REALTIME) in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

        start = clock();
        for(int i = 0; i < count; i++)
                clock_gettime(CLOCK_MONOTONIC, &ts);

        printf("clock_gettime(MONOTONIC) in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

        start = clock();
        for(int i = 0; i < count; i++)
                clock_gettime(CLOCK_REALTIME_COARSE, &ts);

        printf("clock_gettime(REALTIME_COARSE) in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

        start = clock();
        for(int i = 0; i < count; i++)
                clock_gettime(CLOCK_MONOTONIC_COARSE, &ts);

        printf("clock_gettime(MONOTONIC_COARSE) in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

        start = clock();
        for(int i = 0; i < count; i++)
                clock_gettime(CLOCK_MONOTONIC_RAW, &ts);

        printf("clock_gettime(MONOTONIC_RAW) in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

        start = clock();
        for(int i = 0; i < count; i++)
                clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);

        printf("clock_gettime(PROCESS_CPUTIME) in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

        start = clock();
        for(int i = 0; i < count; i++)
                clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);

        printf("clock_gettime(THREAD_CPUTIME) in %f sec\n", (double)(clock() - start)/CLOCKS_PER_SEC);

	return 0;
}

It is awesome!