Upgrade to Pro — share decks privately, control downloads, hide ads and more …

Deoptimization: How YJIT Speeds Up Ruby by Slow...

Avatar for Takashi Kokubun Takashi Kokubun
April 16, 2025
Programming
2
3.1k

Deoptimization: How YJIT Speeds Up Ruby by Slowing Down / RubyKaigi 2025

https://rubykaigi.org/2025
Avatar for Takashi Kokubun

Takashi Kokubun

April 16, 2025
Tweet

More Decks by Takashi Kokubun

See All by Takashi Kokubun
YJIT Makes Rails 1.7x faster / RubyKaigi 2024
Avatar for Takashi Kokubun k0kubun
7
14k
Ruby JIT Hacking Guide / RubyKaigi 2023
Avatar for Takashi Kokubun k0kubun
2
10k
YJIT: Dive into Ruby's JIT compiler written in Rust / Rust.Tokyo 2022
Avatar for Takashi Kokubun k0kubun
1
2.2k
Towards Ruby 4 JIT / RubyKaigi 2022
Avatar for Takashi Kokubun k0kubun
3
11k
Optimizing Production Performance with MRI JIT / RubyConf 2021
Avatar for Takashi Kokubun k0kubun
1
470
Why Ruby's JIT was slow / RubyKaigi Takeout 2021
Avatar for Takashi Kokubun k0kubun
3
1.9k
数時間かかる週一リリースを毎日何度も爆速でできるようにするまで / CI/CD Conference 2021
Avatar for Takashi Kokubun k0kubun
21
14k
Ruby 3 JIT's roadmap / RubyConf China 2020
Avatar for Takashi Kokubun k0kubun
0
830
Ruby 3.0 JIT on Rails
Avatar for Takashi Kokubun k0kubun
9
9.3k

Other Decks in Programming

See All in Programming
ソフトウェア設計とAI技術の活用
Avatar for 増田 亨 masuda220
PRO
17
3.7k
MCPを使ってイベントソーシングのAIコーディングを効率化する / Streamlining Event Sourcing AI Coding with MCP
Avatar for Tomohisa Takaoka tomohisa
0
170
Startups on Rails in Past, Present and Future–Irina Nazarova, RailsConf 2025
Avatar for Irina Nazarova irinanazarova
0
250
Android 16KBページサイズ対応をはじめからていねいに
Avatar for mine2424 mine2424
0
440
状態遷移図を書こう / Sequence Chart vs State Diagram
Avatar for Kuniwak orgachem
PRO
2
200
新メンバーも今日から大活躍！SREが支えるスケールし続ける組織のオンボーディング
Avatar for HonMarkHunt honmarkhunt
5
8.7k
“いい感じ“な定量評価を求めて - Four Keysとアウトカムの間の探求 -
Avatar for Nealle nealle
2
12k
AI時代のソフトウェア開発を考える（2025/07版） / Agentic Software Engineering Findy 2025-07 Edition
Avatar for Takuto Wada twada
PRO
99
37k
코딩 에이전트 체크리스트: Claude Code ver.
Avatar for nacyot nacyot
0
930
Deep Dive into ~/.claude/projects
Avatar for Yuya Hirayama hiragram
14
14k
効率的な開発手段として VRTを活用する
Avatar for Yosuke Ishikawa ishkawa
0
160
AI時代の『改訂新版 良いコード／悪いコードで学ぶ設計入門』 / ai-good-code-bad-code
Avatar for MinoDriven minodriven
23
9.6k

Featured

See All Featured
GitHub's CSS Performance
Avatar for Jon Rohan jonrohan
1031
460k
GraphQLとの向き合い方2022年版
Avatar for Yosuke Kurami quramy
49
14k
A Modern Web Designer's Workflow
Avatar for Chris Coyier chriscoyier
695
190k
Into the Great Unknown - MozCon
Avatar for Noah Learner thekraken
40
1.9k
ReactJS: Keep Simple. Everything can be a component!
Avatar for Pedro Nauck pedronauck
667
120k
Navigating Team Friction
Avatar for Lara Hogan lara
187
15k
How To Stay Up To Date on Web Technology
Avatar for Chris Coyier chriscoyier
790
250k
The MySQL Ecosystem @ GitHub 2015
Avatar for Sam Lambert samlambert
251
13k
Stop Working from a Prison Cell
Avatar for Chris Michel hatefulcrawdad
271
21k
Optimizing for Happiness
Avatar for Tom Preston-Werner mojombo
379
70k
Building Flexible Design Systems
Avatar for Yesenia Perez-Cruz yeseniaperezcruz
328
39k
jQuery: Nuts, Bolts and Bling
Avatar for Doug Neiner dougneiner
63
7.8k

Transcript

  1. Deoptimization: How YJIT Speeds Up Ruby by Slowing Down @k0kubun

    / RubyKaigi 2025

  2. @k0kubun

  3. @k0kubun Z

  4. None

  5. We’re hiring https://candidate.shopify.com/form/ruby-kaigi-2025

  6. None

  7. YJIT

  8. None

  9. https://railsatscale.com/2025-01-10-yjit-3-4-even-faster-and-more-memory-ef fi cient/

  10. None
  11. None

  12. Deoptimization

  13. None

  14. Deoptimization What if you can “slow down” Ruby at any

    time? You can speculatively optimize Ruby and invalidate it later

  15. Playing with Deoptimization Build Ruby with: ./con fi gure --enable-yjit=dev

    Run Ruby with: ruby --yjit-call-threshold=1 --yjit-dump-disasm

  16. Playing with Deoptimization

  17. None

  18. YJIT Deoptimization

  19. Code Patching

  20. None
  21. None
  22. None
  23. None

  24. Rewrite

  25. Rewrite Jump

  26. Global Invalidation

  27. None
  28. None
  29. None

  30. Ruby 3.4’s New YJIT Deoptimization

  31. Invalidation on Escaped Locals

  32. ?

  33. None
  34. None

  35. Invalidation on Singleton Classes

  36. None
  37. None
  38. None
  39. None

  40. Singleton Class Invalidation

  41. Lazy Frame Push

  42. None
  43. None
  44. None

  45. Lazy Frame Push

  46. None
  47. None
  48. None
  49. None

  50. YJIT-only Ruby Methods

  51. Array#each

  52. None
  53. None
  54. None
  55. None
  56. None
  57. None
  58. None

  59. Primitive.attr! :c_trace

  60. Conclusion Deoptimization enables speculative optimizations with lazy invalidation Ruby 3.4

    YJIT optimizes method calls and local variables using deoptimization