Adventures in Garbage Collection: Improving GC Performance in our Massive Monolith (2023)

At the beginning of this year, we ran several experiments aimed at reducing the latency impact of the Ruby garbage collector (GC) in Shopify's monolith. Everything described in this article was a team effort, huge thanks to Jason Hiltz-Laforge for his extended knowledge of our production platform, to Peter Zhu for his deep knowledge of the Ruby garbage collector, as well as to Matt Valentine-House, Étienne Barrié, and Shane Pope for their contributions to this work.In this article we'll talk about the changes we made to improve GC performance, and more importantly, how we got to these changes.