title: how to measure or understand websocket / socket application?
body: <p>In my understanding, websocket/socket has the ability to: </p>
  
  <ol>
  <li>broadcasting: publish messages to the public channel</li>
  <li>private chat room: send messages to a private channel. </li>
  </ol>
  
  <p>so my question is: </p>
  
  <ol>
  <li><p>when broadcasting to a public channel, will the CPU grow high when receiver increase from 10 to 1000 ? </p></li>
  <li><p>when send message to a private channel, is there any tools to measure / optimize? </p></li>
  </ol>
  
  <p>thanks a lot! </p>