Nanosleep too long in any iOS simulator on macOS Sierra

Hi,

Nanosleep in the iOS simulator ( running on MacOS Sierra with xcode 8.1 & 8.2beta ) sleep around 5 times longer than the desired duration.

This doesn't happen on the iPhone 7 or natively in macOS sierra app, only in the simulator.

Is it possible to have more accurate sleep duration in the simulator or is it a bug ?

    struct timespec request; 
    request.tv_sec = 0; 
    request.tv_nsec = 17000000;
  
    mach_timebase_info_data_t base; 
    mach_timebase_info(&base); 
    while (1) { 
        uint64_t start, end, elapsed; 
        start = mach_absolute_time(); 
        nanosleep(&request, NULL); 
        end = mach_absolute_time(); 
        elapsed = (end - start) / base.denom;

       printf("Sleep = %f msec\n", elapsed * 1E-6); 
    }

Output:

Sleep = 84.451425 msec

Sleep = 69.947846 msec

Sleep = 95.484521 msec

Sleep = 72.795438 msec

Sleep = 80.162972 msec

Sleep = 70.265713 msec

...