Explore the latest advancements in Ruby's JIT compiler and its impact on production performance in this 29-minute conference talk from RubyConf 2021. Discover why the JIT compiler initially slowed down production applications like Rails and learn about the recent breakthroughs that have resolved these issues. Gain insights into how Ruby 3.0's JIT compiler now optimizes popular Rails applications, and acquire practical tricks to ensure your production application benefits from these performance enhancements. Delve into topics such as performance optimization for Rails, compilation techniques, and the future of MRI as you uncover ways to achieve easy, free speedups for your Ruby applications.