How fast is Apple Macbook?

My Macbook has Intel Core2 Duo 2.1 GHz. I wrote a small program to do very simple math (trigonometry computation):

#include
#include


int main()
{
double x,y;
long i;

x = 1/3.1415692653;
for(i=0; i<1000000; i++) {
y = i/100000*x;
printf("%lu) sin(%lf) = %lf\n", i, y, sin(y));
}
}

Compile it with:

gcc -mtune=nocona -m64 -msse3 -mfpmath=sse -O3 sin.c -o sin

and execute is as below:

time ./sin

The result is:

real 0m12.345s
user 0m2.624s
sys 0m3.554s

The "real" gives result 12.345 seconds to do 1E6 iterations!, or for each iteration it'd take 12.345E-6 second (12.345 microseconds). Wow!