title: The meaning of strace timestamp
body: <p>When use <code>strace -T -tt -o outputfile myprogram</code>, the out put is like</p>
  <pre><code>16:14:37.576804 write(1, &quot;EFFEEFFFEFFGGEEFEEFECEEDB&quot;..., 4096) = 4096 &lt;0.000014&gt;
  16:14:37.577121 write(1, &quot;,...,,,.\tDEDEEDEDEEBDEEFECECFBEE&quot;..., 4096) = 4096 &lt;0.000015&gt;
  16:14:37.577434 write(1, &quot;66098\tT\t41\t....,.....,,,.,,,,...&quot;..., 4096) = 4096 &lt;0.000016&gt;
  </code></pre>
  <p>Does the first column mean the start time of that system call, or the finish time? As given -T, the last column is given as &quot;Show the time spent in system calls. This records the time difference between the beginning and the end of each system call.&quot; Why is it different from the time gap between two write calls? As the first two, <code>16:14:37.577121 - 16:14:37.576804=0.000317 &gt; 0.000014</code>.</p>