title: Understanding the different clocks of clock_gettime()
body: <p>Hi I wanted to use the <code>clock_gettime()</code> function for measuring the performance of my code. </p>
  
  <p>I am unable to understand the difference between the different kinds of clocks used in the function from the man page descriptions. esp </p>
  
  <pre><code>CLOCK_REALTIME,
  
  CLOCK_PROCESS_CPUTIME_ID
  
  CLOCK_THREAD_CPUTIME_ID
  </code></pre>
  
  <p>Can someone explaing what each of these clocks do?</p>