title: High resolution timer support on 64-bit Linux
body: <p>I'm trying to enable high resolution timer support on 2.6.39.1 64-bit Linux. To do this, I first set <code>CONFIG_HIGH_RES_TIMERS=y</code> in .config. </p>
  
  <p>Also, the output of <code>grep HZ .config</code> is:</p>
  
  <pre><code># CONFIG_RCU_FAST_NO_HZ is not set
  CONFIG_NO_HZ=y
  # CONFIG_HZ_100 is not set
  # CONFIG_HZ_250 is not set
  # CONFIG_HZ_300 is not set
  CONFIG_HZ_1000=y
  CONFIG_HZ=1000
  CONFIG_MACHZ_WDT=m
  </code></pre>
  
  <p>However, the output of the following command is not <code>1 nsec</code> as expected after recompiling the kernel.</p>
  
  <p><code>cat /proc/timer_list |grep resolution</code> prints: <code>.resolution: 999848 nsecs</code></p>
  
  <p>Also, <code>cat /proc/timer_list |grep handler</code> outputs: </p>
  
  <p><code>event_handler:  tick_handle_periodic</code>, instead of <code>event_handler:  hrtimer_interrupt</code></p>
  
  <p>When I ran experiments using <code>hrtimer</code>, I obviously did not see nanosecond precision in the results.</p>
  
  <p>I also tried running the C program mentioned <a href="http://www.advenage.com/topics/linux-timer-interrupt-frequency.php" rel="nofollow">here</a> which is supposed to help determine Linux Kernel Timer Interrupt Frequency. The result of running the C program is as follows:</p>
  
  <p><code>kernel timer interrupt frequency is approx. 766 Hz</code></p>
  
  <p>I'm working on the <a href="http://www.dell.com/us/enterprise/p/poweredge-t710/pd" rel="nofollow">Dell Poweredge T710</a> which, I believe, does have hardware support for high resolution timers(?)</p>
  
  <p>Have I missed any step? Where have I gone wrong?</p>
  
  <p>Thanks!</p>