Understanding Garbage Collection in Ruby

on YouTube ↗21m

" summary

Covers Ruby GC internals (mark/sweep, tricolor marking, compaction, generational GC) and shows how to gather and interpret metrics with GC.stat to find GC-related latency. Explains variable width allocation and highlights using Shopify autotuner middleware to recommend settings. Presents a real Rails monolith upgrade from Ruby 3.1 to 3.3 that causes a 70–80% regression in worst‑case latency and how techniques like process warmup, out-of-band GC and custom background‑job preprocessing restore performance.

AI-written summary · about

" chapters (12)

1. 0:00Introduction and welcome
2. 3:55Memory management in Ruby
3. 6:09Garbage collection as memory manager
4. 9:03Mark and sweep process
5. 10:31Tricolor marking algorithm
6. 12:24Garbage collection performance impact
7. 13:56Generational garbage collection
8. 15:49Debugging garbage collection issues
9. 16:34Shopify's garbage collection autotuner
10. 17:59Case study from Coupa
11. 19:48Out of bound garbage collection
12. 20:08Closing and acknowledgments

" related talks

• 33mRails and the Ruby Garbage Collector: How to Speed Up Your Rails AppPeter Zhu · Rails World 2023
• 42mTweaking Ruby GC Parameters for Fun, Speed, and ProfitHelio Cola · RailsConf 2016
• 34mUnder the Hood of Ruby's Generational Garbage CollectorHemant Kumar · Rocky Mountain Ruby 2014
• 49mRabbit Hole: Garbage Collection and Ruby's FutureChris Kelly · Barcelona Ruby Conference 2013
• 35mThe Hitchhiker's Guide to Ruby GCEric Weinstein · RubyConf 2015
• 38mWhy I am excited about Ruby 2.1?Sam Saffron · RubyConf AU 2014
• 30mBuilding the Next-Generation Garbage Collector in RubyPeter Zhu · RubyConf 2026
• 37mDown the rb_newobj() Rabbit Hole: Garbage Collection in RubyChris Kelly · RubyConf AU 2013