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
4.7k
2

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

https://rubykaigi.org/2025

Avatar for Takashi Kokubun

Takashi Kokubun

April 16, 2025

More Decks by Takashi Kokubun

See All by Takashi Kokubun
Lightning-Fast Method Calls with Ruby 4.1 ZJIT / RubyKaigi 2026
Avatar for Takashi Kokubun k0kubun
3
3.7k
一度始めたらやめられない開発効率向上術 / Findy あなたのdotfilesを教えて！
Avatar for Takashi Kokubun k0kubun
4
3.2k
ZJIT: The Ruby 4 JIT Compiler / Ruby Release 30th Anniversary Party
Avatar for Takashi Kokubun k0kubun
1
550
ZJIT: The Future of Ruby Performance / San Francisco Ruby Conference 2025
Avatar for Takashi Kokubun k0kubun
1
140
ZJIT: Building a New JIT Compiler for Ruby / REBASE 2025
Avatar for Takashi Kokubun k0kubun
0
160
YJIT Makes Rails 1.7x faster / RubyKaigi 2024
Avatar for Takashi Kokubun k0kubun
7
16k
Ruby JIT Hacking Guide / RubyKaigi 2023
Avatar for Takashi Kokubun k0kubun
2
11k
YJIT: Dive into Ruby's JIT compiler written in Rust / Rust.Tokyo 2022
Avatar for Takashi Kokubun k0kubun
2
2.4k
Towards Ruby 4 JIT / RubyKaigi 2022
Avatar for Takashi Kokubun k0kubun
3
12k

Other Decks in Programming

See All in Programming
Japan Community Day at Kubecon + CloudNativeCon Japan 2026: Learning Container Privilege Control by Building My Own Low-Level Container Runtime
Avatar for ternbusty ternbusty
1
170
MySQLとPostgreSQLって何が違うの？
Avatar for 赤神青空 akagami
0
130
【デモ】Kiroで体験する仕様駆動開発｜設計からコーディングまでAIと進める開発フロー
Avatar for 工藤皓夢 cmkudo
0
370
源内ハンズオン概要編
Avatar for Hideyuki Nagata hideg
0
210
AIと壁打ちしながら進めるコスト管理
Avatar for Ryoma Fujiwara fufuhu
2
1.7k
S3 を使うアプリケーションをローカル完結で動かすことに全力を注いでみた / Running S3 Apps Offline
Avatar for Daisuke Garaike contour_gara
0
600
freeeにおけるEvalsの実践例の紹介
Avatar for freee freee
PRO
0
150
Jindong: Introducing Declarative Haptics in Compose Multiplatform
Avatar for HyunWoo Lee l2hyunwoo
0
130
片田舎のおっさん、 Swift Buildのダイアモンド問題解決の不具合修正PRを出すが、解決方法がキャッシュをしないようにすることであり、ビルド時間が伸びると言われてマージされないので高速化もする/swiftbuild
Avatar for yimajo yimajo
0
280
Flow は今どうなっているか
Avatar for mizdra mizdra
PRO
0
710
進化を続けるGo toolsの現在地 / The Current State of Ever-Evolving Go Tools
Avatar for hond hond0413
0
260
AIの中の人になってみる
Avatar for tkym htkym
0
120

Featured

See All Featured
We Have a Design System, Now What?
Avatar for Morgane Peng morganepeng
55
8.3k
Amusing Abliteration
Avatar for ianozsvald ianozsvald
1
260
"I'm Feeling Lucky" - Building Great Search Experiences for Today's Users (#IAC19)
Avatar for Dan Newman danielanewman
230
23k
Designing for Performance
Avatar for Lara Hogan lara
611
70k
The Pragmatic Product Professional
Avatar for Laura Van Doore lauravandoore
37
7.4k
How To Stay Up To Date on Web Technology
Avatar for Chris Coyier chriscoyier
790
250k
Practical Tips for Bootstrapping Information Extraction Pipelines
Avatar for Matthew Honnibal honnibal
25
2k
Context Engineering - Making Every Token Count
Avatar for Addy Osmani addyosmani
9
1.1k
The innovator’s Mindset - 
Leading Through an Era of Exponential Change - McGill University 2025
Avatar for Jean-Marc De Jonghe jdejongh
PRO
1
290
Neural Spatial Audio Processing for Sound Field Analysis and Control
Avatar for NII S. Koyama's Lab skoyamalab
0
410
Optimizing for Happiness
Avatar for Tom Preston-Werner mojombo
378
71k
Building Experiences: Design Systems, User Experience, and Full Site Editing
Avatar for Michelle Schulp Hunt marktimemedia
0
580

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