title: perf: why don't I have "syscall" counters?
body: <p>There are apparently some counters in Linux <code>perf</code> like <code>syscall:sys_enter_select</code>, but on my system <code>perf list</code> does not show any of them</p>
  
  <p>Evidence that other people do have these counters is here: <a href="http://www.brendangregg.com/blog/2014-07-03/perf-counting.html" rel="noreferrer">http://www.brendangregg.com/blog/2014-07-03/perf-counting.html</a></p>
  
  <p>If I run <code>perf top -e 'syscalls:sys_enter_*'</code> it says:</p>
  
  <pre><code>Can't open event dir: Permission denied
  invalid or unsupported event: 'syscalls:sys_enter_*'
  </code></pre>
  
  <p>Other event types (the ones in <code>perf list</code>) work fine.</p>
  
  <p>What do I need to do to access syscall counters in <code>perf</code>?  I'm using Linux kernel and perf version 3.10 on x86_64.</p>