The affinity mask for current process is: 00000003
Checking that affinity mask has been set to 2 ... yes (new affinity is: 00000002)

Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 11 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 10 microseconds 
Counting to 1000 took: 11 microseconds 
Average time taken: 10.133 microseconds

#include <sys/time.h>
#include <sys/resource.h>
#include <stdio.h>

static inline double toseconds(const struct timeval t)
{
return (double)t.tv_sec + (double)t.tv_usec / 1000000.0;
}

static inline unsigned long cycles(void)
{
register unsigned int lo, hi;
asm volatile ("rdtsc" : "=a" (lo), "=d" (hi));
return ((unsigned long)hi << 32UL) | (unsigned long)lo;
}

volatile int dummy = 0;

int main(int argc, char **argv)
{
int arg;
unsigned long c;
long i;
double ssys, suser, swall;
struct timeval begin, end;
struct rusage before, after;

for (arg = 1; arg < argc; arg++) {
char ignore;
if (sscanf(argv[arg], "%ld %c", &i, &ignore) != 1) {
fprintf(stderr, "%s: Invalid number of loop cycles.\n", argv[arg]);
continue;
}
if (i < 1L) {
fprintf(stderr, "%s: Number of loop cycles is too small.\n", argv[arg]);
continue;
}

printf("%lu loops:\n", i);
fflush(stdout);

/* Wait until change at user time in usecs (or secs) */
getrusage(RUSAGE_SELF, &after);
do {
gettimeofday(&begin, NULL);
getrusage(RUSAGE_SELF, &before);
} while (before.ru_utime.tv_sec == after.ru_utime.tv_sec &&
before.ru_utime.tv_usec == after.ru_utime.tv_usec);
gettimeofday(&begin, NULL);
c = cycles();

/* Work loop -- volatile assignment cannot be optimized away. */
while (i-->0L)
dummy = 0;

c = cycles() - c;
gettimeofday(&end, NULL);
getrusage(RUSAGE_SELF, &after);

swall = toseconds(end) - toseconds(begin);
suser = toseconds(after.ru_utime) - toseconds(before.ru_utime);
ssys = toseconds(after.ru_stime) - toseconds(before.ru_stime);

printf("Total cycles: %lu\n", c);
printf("User time: %.6f seconds\n", suser);
printf("System time: %.6f seconds\n", ssys);
printf("Total CPU time: %.6f seconds\n", suser + ssys);
printf("Wall clock: %.6f seconds\n", swall);
printf("\n");
fflush(stdout);
}

return 0;
}