Towards Ruby 4 JIT / RubyKaigi 2022

Transcript

1. Towards Ruby 4 JIT @k0kubun

2. @k0kubun Maintain: MJIT, Haml, ERB Shopify team

3. GitHub Sponsors

4. Haml 6

5. Introduction to Ruby JIT

6. How does Ruby JIT work? Ruby

7. How does Ruby JIT work? 1 + 2 Ruby Abstract

   
 Syntax 
 Tree

8. How does Ruby JIT work? 1 + 2 putobject 1

   putobject 2 opt_plus leave Ruby Abstract 
 Syntax 
 Tree Instruction 
 Sequence 
 (Bytecode)

9. How does Ruby JIT work? 1 + 2 putobject 1

   putobject 2 opt_plus leave Ruby Abstract 
 Syntax 
 Tree Instruction 
 Sequence 
 (Bytecode) Machine 
 Code

10. How does Ruby JIT work?

11. CRuby JIT 1: MJIT

12. CRuby JIT 2: YJIT

13. Current CRuby JITs speed.yjit.org

14. Current CRuby JITs speed.yjit.org

15. Current CRuby JITs • YJIT • Available since Ruby 3.1

    • --jit or --yjit • MJIT • Available since Ruby 2.6 • --mjit

16. Current CRuby JITs • YJIT • Ruby 3.1: x86_64 only,

    no code GC, written in C • Ruby 3.2: arm64 support, (hopefully) code GC, written in Rust • MJIT • Ruby 3.1: Stable-ish, portable, native threads, written in C • Ruby 3.2: Experimental, fork + SIGCHLD, written in Ruby

17. MJIT in Ruby

18. None
19. None

20. mjit.rb: Secret "standard library" in Ruby 3.2 • mjit.rb •

    Even more powerful than TracePoint • You can monkey-patch CRuby JIT • No compatibility guarantee • Every module is private, so const_get is required

21. BYOJ: Bring Your Own JIT

22. BYOJ: Bring Your Own JIT • Load and pause MJIT

    with --mjit=pause • Define RubyVM::MJIT.compile • Use RubyVM::MJIT.const_get(:C) to hack RubyVM • Call RubyVM::MJIT.resume to start JIT With Ruby 3.2:

23. YJIT-style JIT • Monkey-patch RubyVM::MJIT.compile

24. MJIT-style JIT • Monkey-patch RubyVM::MJIT::Compiler.compile

25. MJIT-style JIT

26. Everyone is writing CRuby JIT

27. Benchmarking Ruby JIT

28. yjit-bench

29. yjit-bench • yjit-bench has three kinds of benchmarks: 1. Headlining

    Benchmarks 2. Other Benchmarks 3. Micro Benchmarks

30. 1. Headlining benchmarks • activerecord • hexapdf • liquid-render •

    mail • psych-load • railsbench ✉

31. 2. Other Benchmarks • binarytrees, fankuchredux, nbody • chunky_png •

    erubi, erubi_rails • lee • optcarrot • rubykon

32. 3. Micro Benchmarks • 30k_ifelse, 30k_methods • cfunc_itself, str_concat •

    fib • getivar, setivar • keyword_args • respond_to
33. None

34. Benchmark Your Own JIT • ./run_benchmarks.rb -e “/path/to/ruby --any-option” •

    Pass multiple -e options to compare different JITs

35. Towards Ruby 4 JIT

36. My wish on Ruby 4 JIT • I want Ruby

    4 to be as fast as Java or JavaScript • Ruby 4's performance should be a reason to leave Python
37. None

38. More Concrete Examples

39. None
40. None
41. None

42. Ruby 4 Canary • true is mov-ed (immediate) • No

    opt_* VM instruction • Constant folding • Ruby / C method inlining

43. Ruby 4 Canary’ • Single branch instruction to access @one

    • Single register to access two • No heap allocation • No stack frame
44. None
45. None

46. Ruby 4 Canary 2 • 5000050000 is mov-ed (immediate) •

    Ruby -> C -> Ruby inlining

47. How can we get there?

48. Optimization Challenges 1. Constants 2. Variables 3. Method calls 4.

    Garbage collection

49. 1. Constants

50. 1. Constants

51. 1. Constants

52. 1. Constants

53. 1. Constants

54. 1. Constants

55. 1. Constants

56. 1. Constants

57. 2. Variables

58. 2. Variables

59. 2. Variables

60. 2. Variables

61. 2. Variables

62. 2. Variables

63. 2. Variables

64. 2. Variables

65. 2. Variables

66. 2. Variables

67. 2. Variables

68. 2. Variables 2021 2022 (tomorrow)

69. 3. Method calls

70. 3. Method calls

71. 3. Method calls

72. 3. Method calls

73. 3. Method calls

74. 3. Method calls

75. 3. Method calls • Code locality • Method inlining: C

    㱻 Ruby • Pass arguments with native ABI • Deoptimization on redefinition or interruption (or TracePoint)

76. 4. Garbage collection

77. 4. Garbage collection

78. 4. Garbage collection

79. Next Steps • We still have a lot of rooms

    for improvements on yjit-bench • More cross-instruction optimizations • More method inlining over Ruby and C

80. Conclusion • Build your own JIT with Ruby 3.2 •

    Benchmark your JIT with yjit-bench