Adventures in Garbage Collection: Improving GC Performance in our Massive Monolith - Shopify

This post details specific tuning of Ruby's garbage collector to reduce latency in Shopify's monolith. It addresses major GC triggers like `:oldmalloc` by setting a high limit and `:nofree` by implementing finely-grained preallocation of heap slots using a custom hack and later a Ruby feature. The work involved extensive logging, metric analysis, hypothesis formation, and experimentation, leading to significant reductions in GC time and improved tail latency.