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    <p>I wanted to post this in a comment above but it got much longer than it would allow:</p> <p>Try implementing a simple epoll based server that is entirely asynchronous (steps)</p> <ol> <li>Set up your accept socket ...</li> <li>Add to epoll.</li> <li>enter wait loop: <ol> <li>Check whether event is on accept socket, or normal socket</li> <li>If accept socket, accept connection, add to epoll, go back to 3</li> <li>If event on normal socket for reading, read X bytes, save to write buffer, and enable write event on epoll for socket, go back to 3</li> <li>If event on normal socket for writing, write bytes from buffer to network, disable write event if write buffer is empty, go back to 3.</li> <li>If an error occurs remove the socket from epoll </li> </ol></li> <li>There is no fourth step ... the program should loop forever.</li> </ol> <p>This should remove any complexity you've added from having threading that could cause issues. This moves epoll back into the same sort of domain as <code>select()</code> except that it is generally much faster. The whole idea of using an event library is to know when you can read/write instead of setting a socket to non-blocking, and trying to read from it/write to it.</p> <p>You also never seem to check the return value from <code>write()</code> which may have failed due to receiving a SIGPIPE (I know you ignored the signal, but you will still get an EAGAIN/EINTR errno).</p> <p>The other thing I see is that you are doing a busy loop inside of your thread that is waiting for sockets to be ready. When you use <code>select()</code> or <code>epoll</code> in this case it is so that you are notified that there is something new, so you don't have to do a busy loop...</p> <p>I am not exactly sure what you are attempting to accomplish, but your code is extremely inefficient.</p> <p>What you could do, after implementing just a simple asynchronous example using the steps above is start up multiple worker threads that all listen (using epoll) for <code>read</code> events on the <code>listener</code>/<code>accept</code> socket and have each of the threads handle various connections (still using what I posted above).</p>
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    1. POMissing something or do I just not understand epoll?
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    1. COYeah, I know my code is horribly inefficient :( Honestly, I just wanted it to WORK before I started refactoring. I've been bashing my head on the desk for a while with this one.
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      1. USDavid Young
 

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