Ruby 3.2’s YJIT is Production-Ready - Shopify

This post details significant improvements to YJIT in Ruby 3.2, including a port to Rust for better maintainability and safety, reduced memory usage (cut by approximately one third), improved performance (38% speedup on railsbench over the interpreter), and the addition of ARM64 support. It also highlights additional improvements like object shapes for faster instance variable access, YJIT exit tracing, improved method call support, finer-grained constant cache invalidation, and variable width allocation for objects. Shopify has successfully deployed YJIT globally on its SFR infrastructure, measuring real speedups of 5% to 10%.