No Callbacks, No Threads: Async & Cooperative Web Servers with Ruby 1.9

Multi-threaded servers compete for the global interpreter lock (GIL) and incur the cost of continuous context switching, potential deadlocks, or plain wasted cycles. Asynchronous servers, on the other hand, create a mess of callbacks and errbacks, complicating the code. But, what if, you could get all the benefits of asynchronous programming, while preserving the synchronous look and feel of the code – no threads, no callbacks?

In this talk we’ll look at how Ruby 1.9 Fibers, combined with EventMachine, can enable us to build a fully asynchronous web-server, while preserving the feeling of synchronous code – the best of both worlds. A cooperative, pure IO-scheduled web server to power your next Rails, or Rack application!

We will dive deep into the architecture, libraries, and internals of Ruby:

• Limitations of threaded web servers, libraries and the global interpreter lock
• (Dis)advantages of asynchronous network programming with the EventMachine library
• Changes to Ruby 1.9 threading, GIL, and introduction of Fibers
• Cooperative IO scheduling in Ruby 1.9: Pro’s & Cons
• Fibers + Callbacks: next generation Ruby web-server