Interview with Aaron Patterson [audio]

Ruby core team member Aaron Patterson (tenderlove) takes us deep into the cutting edge of Ruby's performance frontier in this technical exploration of how one of the world's most beloved programming languages continues to evolve.

At Shopify, Aaron works on two transformative projects: ZJIT, a method-based JIT compiler that builds on YJIT's success by optimizing register allocation to reduce memory spills, and enhanced Ractor support to enable true CPU parallelism in Ruby applications. He explains the fundamental differences between these approaches - ZJIT makes single CPU utilization more efficient, while Ractors allow Ruby code to run across multiple CPUs simultaneously.

The conversation reveals how real business needs drive language development. Shopify's production workloads unpredictably alternate between CPU-bound and IO-bound tasks, creating resource utilization challenges. Aaron's team aims to build auto-scaling web server infrastructure using Ractors that can dynamically adjust to workload characteristics - potentially revolutionizing how Ruby applications handle variable traffic patterns.

For developers interested in contributing to Rails, Aaron offers practical advice: start reading the source code, understand the architecture, and look for ways to improve it. He shares insights on the challenges of making Rails Ractor-safe, particularly around passing lambdas between Ractors while maintaining memory safety.

The episode concludes with a delightful tangent into Aaron's latest hardware project - building a color temperature sensor for camera calibration that combines his photography hobby with his programming expertise. True to form, even his leisure activities inevitably transform into coding projects.

Whether you're a seasoned Ruby developer or simply curious about language design and performance optimization, Aaron's unique blend of deep technical knowledge and playful enthusiasm makes this an engaging journey through Ruby's exciting future.