Going faster with InvokeDynamic

InvokeDynamic is a new instruction for the Java 7 VM which allows language implementers to handle method dispatch for any language quickly. This talk covers the basics of how it works and what it enables in JRuby 1.7

Transcript

1. Going faster with InvokeDynamic Tony Arcieri JRuby SF Meetup May 17th, 2012
2. Why am I qualified?
4. I’m trying! InDy is a technical subject o_O
5. HotSpot 101
6. Java was slow Once upon a time...
8. HotSpot Just-In-Time Compiler
9. Start by interpreting JVM “emulates” bytecodes in software BYTECODE
10. Locate “hot spots” BYTECODE Using runtime profiling information
11. Generate machine code Compile JVM bytecode to native ISA BYTECODE 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
12. Inlining Combine and optimize across calls Method 1 CALL Method 2
13. Inlining Combine and optimize across calls Method 1 Method 2
14. Ruby was slow Once upon a time...
15. Ruby with JIT •JRuby •Rubinius •MacRuby
16. JRuby JIT
17. Architecture Diagram
18. Start by interpreting Walk the parse tree RUBY
19. Locate “hot spots” RUBY Over 50 method invocations
20. Compile to bytecode RUBY Ruby code becomes JVM instructions B Y T E C O D E B Y T E C O D E B Y T E C O D E B Y T E C O D E B Y T E C O D E
21. HotSpot JITs too RUBY Ruby code becomes machine code B Y T E C O D E B Y T E C O D E 1 0 1 0 1 0 1 0 1 0 1 0
22. JVM Limitations
23. Made for Java •InvokeVirtual •InvokeInterface •InvokeStatic •InvokeSpecial
24. JVM is smart! •C++ virtual methods: SLOW! •InvokeVirtual: FAST!
25. JVM = old dog Can’t learn new tricks
26. Y U NO InvokeRuby?
27. Y U NO InvokeRuby? Y U NO InvokeGroovy? Y U NO InvokeJavaScript? Y U NO InvokeClojure?
28. What if we could teach the JVM the fast path?
29. What if it worked for any language?
30. One Invoke to rule them all!
31. How?
32. InvokeDynamic
33. InDy
34. InDy •Shipped in Java 7 •Supported in JRuby 1.7 •JRuby 1.7 release preview available next week!
35. What is InDy?
36. New JVM instruction
37. method_missing for Invoke
38. InDy is a “callback”
39. Bootstrap method
40. Bootstrap method Wire up the call site
41. Bootstrap method Your own code!
42. Bootstrap Method •Called on all classes that use InDy •Find MethodHandle to dispatch •Return CallSite object
43. Bootstrap Method •Invoked the first time a call site is used •Resulting call site object is “bound” to where InDy was invoked and is used for subsequent calls •CallSites can designate their own caching behavior
45. InDy Review •Bootstrap method •MethodHandles •CallSite
46. Result?
47. Java speed! Seriously
48. Inlining Combine and optimize across calls Method 1 Method 2
50. Will it inline?
51. Method invocation? foo.bar baz
52. YES
53. Super? super(foo, bar, baz)
54. YES
55. Splats? foo(bar, *baz)
56. Default arguments? def foo(bar, baz = Qux.new) ... end
57. YES
58. InDy can convert arguments
59. Argument Conversion = MethodHandle
60. send
61. YES
62. method_missing
63. YES
64. Java code?
65. YES
66. JRuby runtime?
67. YES
68. Core types?
69. YES
70. Conclusion
71. JVM can learn new tricks
72. Ruby can be fast on the JVM
73. Ruby can be Java speed on the JVM
74. Any language can be Java speed on the JVM
75. As long as you know InDy...
76. One more thing...
77. This is the greatest thing that has ever happened to the JVM
78. Your wildest dreams
79. ...are possible!
80. Questions? Ask @headius on Twitter
81. Questions? I can try o_O
82. Twitter: @bascule Celluloid: celluloid.io Blog: unlimitednovelty.com