title: Code to measure EXACT execution time inside code on iPad or Phone?
body: <p>Is is any difference between using <strong>mach_absolute_time</strong> and the simple <strong>NSDate</strong> method explained by golden eagle below?</p>
  
  <p>Here's an excellent explanation of using the mach approach...</p>
  
  <p><a href="https://stackoverflow.com/questions/646815/how-do-i-accurately-time-how-long-it-takes-to-call-a-function-on-the-iphone/647129#647129">How do I accurately time how long it takes to call a function on the iPhone?</a></p>
  
  <p>and</p>
  
  <p><a href="https://stackoverflow.com/questions/2673966">Measure time between library call and callback</a></p>