Improving CVAR performance in Ruby 3.1

on YouTube ↗28m

" summary

Announces a concrete change: Ruby 3.1 adds a class variable cache implemented as an inline cache stored on the topmost class that tracks global_cvar_state and skips repeated ancestor walks. Microbenchmarks show class variable access was 8.5× slower with 100 modules vs one, and railbench yields +42 RPS (about 6–7% faster, 615 → 657 RPS). The cache eliminates progressive slowdown and shows real-world speedup without code changes.

AI-written summary · about

" chapters (9)

1. 0:00Start
2. 2:59Class Variables
3. 3:40Class Instance Variables
4. 6:45Class Variables and Instance Variables Are Stored in the Same Hash Table Structure in Ruby
5. 8:58Benchmarks
6. 15:50Railsbench
7. 24:34Learn C
8. 25:08How Ruby Is Designed
9. 25:29Contributing to Ruby

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