title: Flamegraph shows a lot of overhead from perf_event
body: <p>I am new to BPF and perf, I am using</p>
  <pre><code>perf record -F 150 -g -p $(pidof  app_name)  -- sleep  60
  </code></pre>
  <p>to profiling a pub sub based app,  the publisher side is around 100HZ.
  and flamegraph is dominated by perf_event, which I think it is related to the tracing. My question:</p>
  <ol>
  <li>is this normal ? I perf-ed other toy example(non-pub-sub), which does not have  this kind of overhead showing up.</li>
  <li>what is the tuning trick I can do to perf my own app ? without showing the overhead of the perf itself ?</li>
  </ol>
  <p><a href="https://i.stack.imgur.com/w5JLy.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/w5JLy.png" alt="enter image description here" /></a></p>
  <p><a href="https://i.stack.imgur.com/umcFn.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/umcFn.png" alt="enter image description here" /></a></p>