Upgrade to PRO for Only $50/Year—Limited-Time Offer! 🔥

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

Avatar for Takashi Kokubun Takashi Kokubun
April 16, 2025
Programming
2
3.6k

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
ZJIT: The Ruby 4 JIT Compiler / Ruby Release 30th Anniversary Party
Avatar for Takashi Kokubun k0kubun
0
11
ZJIT: The Future of Ruby Performance / San Francisco Ruby Conference 2025
Avatar for Takashi Kokubun k0kubun
1
48
ZJIT: Building a New JIT Compiler for Ruby / REBASE 2025
Avatar for Takashi Kokubun k0kubun
0
36
YJIT Makes Rails 1.7x faster / RubyKaigi 2024
Avatar for Takashi Kokubun k0kubun
7
15k
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
2
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
500
Why Ruby's JIT was slow / RubyKaigi Takeout 2021
Avatar for Takashi Kokubun k0kubun
3
2k

Other Decks in Programming

See All in Programming
Full-Cycle Reactivity in Angular: SignalStore mit Signal Forms und Resources
Avatar for Manfred Steyer manfredsteyer
PRO
0
150
dotfiles 式年遷宮 令和最新版
Avatar for masawada masawada
1
790
新卒エンジニアのプルリクエスト with AI駆動
Avatar for Yuta Fukunaga fukunaga2025
0
230
【CA.ai #3】ワークフローから見直すAIエージェント — 必要な場面と“選ばない”判断
Avatar for SatoAoaka satoaoaka
0
260
エディターってAIで操作できるんだぜ
Avatar for kis9a kis9a
0
740
「コードは上から下へ読むのが一番」と思った時に、思い出してほしい話
Avatar for HideyukiKitao panda728
PRO
39
26k
The Past, Present, and Future of Enterprise Java
Avatar for ivargrimstad ivargrimstad
0
170
JETLS.jl ─ A New Language Server for Julia
Avatar for abap34 abap34
1
420
Tinkerbellから学ぶ、Podで DHCPをリッスンする手法
Avatar for Tomofumi Kondo tomokon
0
140
WebRTC、 綺麗に見るか滑らかに見るか
Avatar for sublimer sublimer
1
190
AIコーディングエージェント（skywork）
Avatar for kondai kondai24
0
180
AIコーディングエージェント（Gemini）
Avatar for kondai kondai24
0
240

Featured

See All Featured
The Myth of the Modular Monolith - Day 2 Keynote - Rails World 2024
Avatar for Eileen M. Uchitelle eileencodes
26
3.3k
Making the Leap to Tech Lead
Avatar for Ryan Cromwell cromwellryan
135
9.7k
世界の人気アプリ100個を分析して見えたペイウォール設計の心得
Avatar for Akihiro Kokubo akihiro_kokubo
PRO
63
35k
The Illustrated Children's Guide to Kubernetes
Avatar for Chris Short chrisshort
51
51k
Java REST API Framework Comparison - PWX 2021
Avatar for Matt Raible mraible
34
9k
The Cost Of JavaScript in 2023
Avatar for Addy Osmani addyosmani
55
9.4k
Designing for Performance
Avatar for Lara Hogan lara
610
69k
Claude Code のすすめ
Avatar for schroneko schroneko
65
200k
From Legacy to Launchpad: Building Startup-Ready Communities
Avatar for Dug Song dugsong
0
110
Chasing Engaging Ingredients in Design
Avatar for Sebastian Deterding codingconduct
0
71
HDC tutorial
Avatar for Michiel Stock michielstock
0
250
Reflections from 52 weeks, 52 projects
Avatar for Jefferson Lam jeffersonlam
355
21k

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