Some extensive background to the speedups that occurred in 1.9.3 with regards to loading so far along with the Xavier Shay work that didn't get included: <a href="http://www.rubyinside.com/ruby-1-9-3-faster-loading-times-require-4927.html" rel="nofollow">http://www.rubyinside.com/ruby-1-9-3-faster-loading-times-re...</a>
This is exciting, the load time is one of the things that is most painful for me when working with Rails. It's really great when you can just add gems and get things working quickly but the load time tends to shoot through the roof...<p>Spork etc help but you still end up spending a lot of time waiting.
The falcon patches for 1.9.3 together with GC tuning boosted our rails loading time by over 400% (Thanks to the answer on <a href="http://stackoverflow.com/questions/12892937/improve-rails-loading-time" rel="nofollow">http://stackoverflow.com/questions/12892937/improve-rails-lo...</a>). It's easy to see how required gems add up to the loading time, so I hope to see some more improvements.<p>This affects a lot of things: going into the console, running the server, running tests, running migrations, rake tasks etc...<p>Not trying to start a flame war, but I recently compared a live rails project with another live django project I was working on. Django was loading in under 1 second. Rails took almost 50 on a similar-spec host. Apples and Oranges. I know. After applying the falcon patches it dropped down to around 11 seconds. There's still an order-of-magnitude difference, but it's nice to see things going in the right direction.
For a really fast Rails environment I highly recommend Zeus <a href="https://github.com/burke/zeus" rel="nofollow">https://github.com/burke/zeus</a> which is built in Go. It does a great job of reloading only the dependencies that have changed.