Using rails-perftest with Rails 4.1 and Ruby 2.1

Question

In Railscasts 411 Performance Testing http://railscasts.com/episodes/411-performance-testing Ryan has us patch the garbage collector in our version Ruby. He's using Ruby 1.9.3. Is this still required for Ruby 2.1.1, with its new garbage collector? if so, follow the same instructions? Without it, the memory perftest generates no data.