PHP and COMET. Need to be guided

I was looking for creating live websites using PHP. (COMET) I was looking for a very long time. (about a month) I even checked some PHP chat scripts and used them on my web server, but I had some problems for most of them. (to be explained)

So far, most people have said the same thing: PHP is not the best language that can be used with COMET. Chat / comet examples are hacked at best.

I ask about this because I want to have some features on my websites, for example, to allow users to chat with each other. This is where I need a live connection to PHP pages. I also plan to make a browser-based game, and a live connection will still be required!

AJAX was a rare thing 2 years ago, featured on Facebook. Now almost everyone uses it, and this has become the standard for web development. Now COMET-based websites are growing. Youtube, Google+, Facebook, EA Battlelog, etc. I believe that I should learn to use it.

Ok, here are my questions. (Some of the information below is the one I collected while searching on Google. Not sure if they are correct or not.)

• Some languages, such as Python, have dedicated web servers designed for this to work. I believe one of them is called Tornado Web Server. Designed and tuned to simulate thousands of live connections. I believe Appserv doesn’t have that option, but some people said that NGINX can handle it with a decent configuration. It's true? What configurations should be made? Are there any PHP web servers for this to work?

• Some of the most popular things are:

  and. Using APE.

  b. Using Socket.IO

  with. Node.js

  Can I use them with PHP? Which one is the most promising? Could you give them some guidance? Is there anything else?

• script. , flush() , usleep() . ( , )

  while(true)
  {
      // query database
     // output the result
     // flush the browser
     // sleep for few seconds to lower cpu load 
  }
  

usleep() - Windows. usleep() , Windows? , "" PHP-? , , % 100 WIN UNIX.

• PHP "" ? PHP ? , ? ( . , HTML5 AS3, AS3 , JS .)

• WebSync? PHP?

, , COMET :

• script, .
• . JSON/AJAX , , . ( , , .)

, . , , . setInterval() COMET, .