Since the C10K problem, event loops have been used together with IO multiplexors to solve IO scalability issues. There are different event loops which can be used in Python, some high level ones like Twisted or Tornado, and some low level ones like pyev or pyuv, or you can even roll your own!

As the author of pyuv I'll go through the inners of the libuv low level event loop and show how it can be used to build a higher level one, that is, how to use it with Twisted, Tornado and even Gevent.