title: SO_TIMESTAMP for tsc not timeval?
body: <p>As can be seen in the <a href="http://linux.die.net/man/7/socket" rel="nofollow">socket man page</a>, one can use <code>SO_TIMESTAMP</code> with <code>setsockopt</code> to 
  measure the amount of time it takes the Linux kernel to hand a received network packet off to user space.</p>
  
  <p>There is a good description of this functionality here: <a href="http://vilimpoc.org/research/ku-latency/" rel="nofollow">Measuring latency in the Linux network stack between kernel and user space</a>.</p>
  
  <p>Is there any way to get a reading of the <code>tsc</code> rather than a <code>timeval</code> at the time the kernel received a packet?</p>