Miniboxing Library - Scala.world

Miniboxing Library - Scala.world

Transcript

1. scala-miniboxing.org @miniboxing 12th of September 2016 scala.world Penrith, UK The Story of a Parallel Scala Library
2. scala-miniboxing.org @miniboxing The Story of a Parallel Scala Library The constructs used by miniboxing to optimize your code 12th of September 2016 scala.world Penrith, UK
3. scala-miniboxing.org @miniboxing Miniboxing Miniboxing • Compiler transformation
4. scala-miniboxing.org @miniboxing Miniboxing Miniboxing • Compiler transformation • Improves performance of generics – When instantiated by primitive types
5. scala-miniboxing.org @miniboxing Miniboxing Miniboxing • Compiler transformation • Improves performance of generics – When instantiated by primitive types • Introduces optimized constructs – Automatically – Or with programmer help
6. scala-miniboxing.org @miniboxing Miniboxing Miniboxing • Compiler transformation • Improves performance of generics – When instantiated by primitive types • Introduces optimized constructs – Automatically – Or with programmer help
7. scala-miniboxing.org @miniboxing STOP Please ask if things are not clear!
8. scala-miniboxing.org @miniboxing Motivation Motivation • We build cool new constructs and paradigms for { conn getConnection \/> "Could not connect" ← ids conn.get("id") \/> "Coult not get ids" ← } yield user
9. scala-miniboxing.org @miniboxing Motivation Motivation • We build cool new constructs and paradigms • But some constructs are deeply integrated • Functions • Tuples • Arrays • Ordering • Numeric for { conn getConnection \/> "Could not connect" ← ids conn.get("id") \/> "Coult not get ids" ← } yield user
10. scala-miniboxing.org @miniboxing Motivation Motivation val x = (x: Int) => x
11. scala-miniboxing.org @miniboxing Motivation Motivation val x = (x: Int) => x Function syntax is sugar for anonymous classes extending FunctionX traits (or for Java8 lambdas)
12. scala-miniboxing.org @miniboxing Motivation Motivation val x = (x: Int) => x Extending Function1 behavior? Sure, add an implicit. Function syntax is sugar for anonymous classes extending FunctionX traits (or for Java8 lambdas)
13. scala-miniboxing.org @miniboxing Motivation Motivation val x = (x: Int) => x Extending Function1 behavior? Sure, add an implicit. Changing behavior (e.g. PartialFunction)? This is what we'll talk about today. Function syntax is sugar for anonymous classes extending FunctionX traits (or for Java8 lambdas)
14. scala-miniboxing.org @miniboxing Extending vs Changing Behavior Extending vs Changing Behavior Adding a new method to the trait/class
15. scala-miniboxing.org @miniboxing Extending vs Changing Behavior Extending vs Changing Behavior Adding a new method to the trait/class Making it conform to an interface
16. scala-miniboxing.org @miniboxing Extending vs Changing Behavior Extending vs Changing Behavior Adding a new method to the trait/class Making it conform to an interface Changing a method's signature
17. scala-miniboxing.org @miniboxing Extending vs Changing Behavior Extending vs Changing Behavior Adding a new method to the trait/class Making it conform to an interface Changing a method's signature Updating the body of a method
18. scala-miniboxing.org @miniboxing Extending vs Changing Behavior Extending vs Changing Behavior Adding a new method to the trait/class Making it conform to an interface Changing a method's signature Updating the body of a method Changing the fields of a class
19. scala-miniboxing.org @miniboxing Extending vs Changing Behavior Extending vs Changing Behavior Adding a new method to the trait/class Making it conform to an interface Changing a method's signature Updating the body of a method Changing the fields of a class Extending behavior Changing behavior
20. scala-miniboxing.org @miniboxing Extending vs Changing Behavior Extending vs Changing Behavior Why would you need that? Adding a new method to the trait/class Making it conform to an interface Changing a method's signature Updating the body of a method Changing the fields of a class Extending behavior Changing behavior
21. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing
22. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Data Representation Mixing Representations Library Interoperation
23. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Data Representation Mixing Representations Library Interoperation
24. scala-miniboxing.org @miniboxing Erased Generics Erased Generics def identity[T](t: T): T = t def identity(t: Object): Object = t scalac / javac
25. scala-miniboxing.org @miniboxing Erased Generics Erased Generics identity(5) identity(java.lang.Integer.valueOf(5)) scalac / javac
26. scala-miniboxing.org @miniboxing Erased Generics Erased Generics identity(5) identity(java.lang.Integer.valueOf(5)) scalac / javac boxed data representation
27. scala-miniboxing.org @miniboxing Erased Generics Erased Generics java.lang.Integer.valueOf(5) boxing is not great ... boxing is not great ... inflates heap requirements produces garbage value is accessed indirectly (slow) breaks locality guarantees
28. scala-miniboxing.org @miniboxing Specialization Specialization def identity[T](t: T): T = t def identity(t: Object): Object = t specialization def identity_Z(t: bool): bool = t
29. scala-miniboxing.org @miniboxing Specialization Specialization def identity[T](t: T): T = t def identity(t: Object): Object = t specialization def identity_Z(t: bool): bool = t def identity_C(t: char): char = t
30. scala-miniboxing.org @miniboxing Specialization Specialization def identity[T](t: T): T = t def identity(t: Object): Object = t specialization def identity_Z(t: bool): bool = t def identity_C(t: char): char = t … (7 other variants)
31. scala-miniboxing.org @miniboxing Specialization Specialization identity(5) identity_I(5) specialization
32. scala-miniboxing.org @miniboxing Specialization Specialization identity(5) identity_I(5) specialization No boxing, it automatically calls the specialized variant for integers
33. scala-miniboxing.org @miniboxing Specialization Specialization def tupled[T1, T2](t1: T1, t2: T2) ... // 100 methods (102) specialization
34. scala-miniboxing.org @miniboxing Specialization Specialization def tupled[T1, T2](t1: T1, t2: T2) ... // 100 methods (102) specialization Can we do better?
35. scala-miniboxing.org @miniboxing The idea behind The idea behind ... LONG DOUBLE INT FLOAT SHORT ... LONG DOUBLE INT FLOAT SHORT a long integer miniboxing miniboxing
36. scala-miniboxing.org @miniboxing Miniboxing Miniboxing def identity[T](t: T): T = t def identity(t: Object): Object = t miniboxing def identity_M(..., t: long): long = t
37. scala-miniboxing.org @miniboxing Miniboxing Miniboxing def identity[T](t: T): T = t def identity(t: Object): Object = t miniboxing def identity_M(..., t: long): long = t long encodes all primitive types
38. scala-miniboxing.org @miniboxing Miniboxing Miniboxing def identity[T](t: T): T = t def identity(t: Object): Object = t miniboxing def identity_M(..., t: long): long = t Only 2n variants long encodes all primitive types
39. scala-miniboxing.org @miniboxing Miniboxing Miniboxing identity(3) identity_M(..., int2minibox(3)) miniboxing
40. scala-miniboxing.org @miniboxing Miniboxing Miniboxing identity(3) identity_M(..., int2minibox(3)) miniboxing The miniboxed variant of identity
41. scala-miniboxing.org @miniboxing Miniboxing Miniboxing identity(3) identity_M(..., int2minibox(3)) miniboxing The miniboxed variant of identity Unlike boxing, these conversions do not affect performance
42. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Data Representation Mixing Representations Library Interoperation
43. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Data Representation Mixing Representations Library Interoperation
44. scala-miniboxing.org @miniboxing Call Graph Call Graph def foo[T](t: T): T = bar(t) def bar[T](t: T): T = baz(t) def baz[T](t: T): T = t call graph
45. scala-miniboxing.org @miniboxing Call Graph Call Graph foo bar baz
46. scala-miniboxing.org @miniboxing Miniboxed Call Graph Miniboxed Call Graph def foo[@miniboxed T](t: T): T = bar(t) def bar[@miniboxed T](t: T): T = baz(t) def baz[@miniboxed T](t: T): T = t miniboxing
47. scala-miniboxing.org @miniboxing Miniboxed Call Graph Miniboxed Call Graph def foo(...): ... = bar(...) def foo_M(...): ... = bar_M(...) def bar(...): ... = baz(...) def bar_M(...): ... = baz_M(...) def baz(...): ... = t def baz_M(...): ... = t
48. scala-miniboxing.org @miniboxing Miniboxed Call Graph Miniboxed Call Graph foo foo_M bar bar_M baz baz_M
49. scala-miniboxing.org @miniboxing Miniboxed Call Graph Miniboxed Call Graph foo foo_M bar bar_M baz baz_M Data is passed in the miniboxed encoding no boxing necessary!
50. scala-miniboxing.org @miniboxing Suboptimal Call Graph Suboptimal Call Graph def foo[@miniboxed T](t: T): T = bar(t) def bar[@miniboxed T](t: T): T = baz(t) def baz[@miniboxed T](t: T): T = t miniboxing
51. scala-miniboxing.org @miniboxing Suboptimal Call Graph Suboptimal Call Graph foo foo_M bar baz baz_M
52. scala-miniboxing.org @miniboxing Suboptimal Call Graph Suboptimal Call Graph foo foo_M bar baz baz_M no bar_M to call box →
53. scala-miniboxing.org @miniboxing Suboptimal Call Graph Suboptimal Call Graph foo foo_M bar baz baz_M no bar_M to call box →
54. scala-miniboxing.org @miniboxing Suboptimal Call Graph Suboptimal Call Graph foo foo_M bar baz baz_M no bar_M to call box →
55. scala-miniboxing.org @miniboxing Suboptimal Call Graph Suboptimal Call Graph foo foo_M bar baz baz_M no bar_M to call box → not enough info to return to the optimized trace
56. scala-miniboxing.org @miniboxing Suboptimal Call Graph Suboptimal Call Graph scala> object Test { | def foo[@miniboxed T](t: T): T = bar(t) | def bar[ T](t: T): T = baz(t) | def baz[@miniboxed T](t: T): T = t | } <console>:10: warning: The method Test.bar would benefit from miniboxing type parameter T, since it is instantiated by miniboxed type parameter T of method foo: def foo[@miniboxed T](t: T): T = bar(t) ^ <console>:11: warning: The following code could benefit from miniboxing specialization if the type parameter T of method bar would be marked as "@miniboxed T": def bar[T](t: T): T = baz(t) ^ defined object Test
57. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Data Representation Mixing Representations Library Interoperation
58. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Data Representation Mixing Representations Library Interoperation
59. scala-miniboxing.org @miniboxing Library Interoperation Library Interoperation scala> def identityFun[T] = (t: T) => t defined method identityFun
60. scala-miniboxing.org @miniboxing Library Interoperation Library Interoperation scala> def identityFun[T] = (t: T) => t defined method identityFun scala> identityFun(3) <console>:11: warning: The method identityFun would benefit from miniboxing type parameter T, since it is instantiated by a primitive type. identityFun(3) ^ res1: Int = 3
61. scala-miniboxing.org @miniboxing scala> def identityFun[@miniboxed T] = (t: T) => t Library Interoperation Library Interoperation
62. scala-miniboxing.org @miniboxing scala> def identityFun[@miniboxed T] = (t: T) => t <console>:12: warning: The type parameter T1 of trait scala.Function1 is specialized but to interoperate efficiently with miniboxing, it would have to be miniboxed. def identityFun[@miniboxed T] = (t: T) => t ^ <console>:12: warning: The type parameter R of trait scala.Function1 is specialized but to interoperate efficiently with miniboxing, it would have to be miniboxed. def identityFun[@miniboxed T] = (t: T) => t ^ defined method identityFun Library Interoperation Library Interoperation
63. scala-miniboxing.org @miniboxing scala> def identityFun[@miniboxed T] = (t: T) => t <console>:12: warning: The type parameter T1 of trait scala.Function1 is specialized but to interoperate efficiently with miniboxing, it would have to be miniboxed. def identityFun[@miniboxed T] = (t: T) => t ^ <console>:12: warning: The type parameter R of trait scala.Function1 is specialized but to interoperate efficiently with miniboxing, it would have to be miniboxed. def identityFun[@miniboxed T] = (t: T) => t ^ defined method identityFun Library Interoperation Library Interoperation Not actionable
64. scala-miniboxing.org @miniboxing scala> def identityFun[@miniboxed T] = (t: T) => t <console>:12: warning: The type parameter T1 of trait scala.Function1 is specialized but to interoperate efficiently with miniboxing, it would have to be miniboxed. def identityFun[@miniboxed T] = (t: T) => t ^ <console>:12: warning: The type parameter R of trait scala.Function1 is specialized but to interoperate efficiently with miniboxing, it would have to be miniboxed. def identityFun[@miniboxed T] = (t: T) => t ^ defined method identityFun Library Interoperation Library Interoperation Not actionable Need to fix it
65. scala-miniboxing.org @miniboxing scala> def identityFun[@miniboxed T] = (t: T) => t <console>:12: warning: The type parameter T1 of trait scala.Function1 is specialized but to interoperate efficiently with miniboxing, it would have to be miniboxed. def identityFun[@miniboxed T] = (t: T) => t ^ <console>:12: warning: The type parameter R of trait scala.Function1 is specialized but to interoperate efficiently with miniboxing, it would have to be miniboxed. def identityFun[@miniboxed T] = (t: T) => t ^ defined method identityFun Library Interoperation Library Interoperation Not actionable Need to fix it
66. scala-miniboxing.org @miniboxing Library Interoperation Library Interoperation • Multiple such constructs – Functions automatic, most interesting → – Arrays need user intervention, warnings → – Tuples automatic → – Numeric automatic, but I was lazy →
67. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Data Representation Mixing Representations Library Interoperation
68. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing
69. scala-miniboxing.org @miniboxing MbFunctionX MbFunctionX • Miniboxed replacement for FunctionX • Assumptions – Function created once – Called multiple times optimize for calling → overhead
70. scala-miniboxing.org @miniboxing MbFunctionX MbFunctionX • Miniboxed replacement for FunctionX • Assumptions – Function created once – Called multiple times optimize for calling → overhead Let's see how we transform
71. scala-miniboxing.org @miniboxing MbFunctionX MbFunctionX • Three approaches – trait Function0[@miniboxed @specialized R] • Incompatible transformations, won't fly – Call-site adaptation (implicit + value class) • call overhead – Replace FunctionX body • no call overhead
72. scala-miniboxing.org @miniboxing Library Interoperation Library Interoperation scala> def identityFun[@miniboxed T] = (t: T) => t defined method identityFun
73. scala-miniboxing.org @miniboxing Library Interoperation Library Interoperation scala> def identityFun[@miniboxed T] = (t: T) => t defined method identityFun def identityFun[@miniboxed T]: MbFunction1[T, T] = ...
74. scala-miniboxing.org @miniboxing Library Interoperation Library Interoperation scala> def identityFun[@miniboxed T] = (t: T) => t defined method identityFun def identityFun[@miniboxed T]: MbFunction1[T, T] = ... Once this is done, miniboxing does its magic
75. scala-miniboxing.org @miniboxing Library Interoperation Library Interoperation scala> def identityFun[@miniboxed T] = (t: T) => t defined method identityFun def identityFun[@miniboxed T]: MbFunction1[T, T] = ... Once this is done, miniboxing does its magic def identityFun[T]: MbFunction1[T, T] = { class $anon extends MbFunction1_L[T, T] { def apply(t: T) = t } new $anon() } def identityFun_M[Tsp](...): MbFunction1[T, T] = { class $anon extends MbFunction1_M[T, T](...) { def apply_M(..., t: T) = t } new $anon() }
76. scala-miniboxing.org @miniboxing Library Interoperation Library Interoperation • Multiple such constructs – Functions automatic, most interesting → – Arrays need user intervention, warnings → – Tuples automatic → – Numeric automatic, but I was lazy →
77. scala-miniboxing.org @miniboxing Extending vs Changing Behavior Extending vs Changing Behavior Adding a new method to the trait/class Making it conform to an interface Changing a method's signature Updating the body of a method Changing the fields of a class Extending behavior Changing behavior
78. scala-miniboxing.org @miniboxing Extending vs Changing Behavior Extending vs Changing Behavior Adding a new method to the trait/class Making it conform to an interface Changing a method's signature Updating the body of a method Changing the fields of a class Extending behavior Changing behavior Completely replacing a library class
79. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing
80. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Dependencies Reverse deps Object model
81. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Dependencies Reverse deps Object model
82. scala-miniboxing.org @miniboxing Dependencies Dependencies Your library
83. scala-miniboxing.org @miniboxing Dependencies Dependencies Your library Scala stdlib Other library Other library dependencies
84. scala-miniboxing.org @miniboxing Dependencies Dependencies Your library Scala stdlib Other library Other library dependencies
85. scala-miniboxing.org @miniboxing Dependencies Dependencies Your library Scala stdlib Other library Other library dependencies Each library is free to use its desired FunctionX version
86. scala-miniboxing.org @miniboxing Dependencies Dependencies Your library Scala stdlib Other library Other library dependencies Each library is free to use its desired FunctionX version Talk to each in its own "language"
87. scala-miniboxing.org @miniboxing Dependencies Dependencies Your library Scala stdlib Other library Other library dependencies Each library is free to use its desired FunctionX version Talk to each in its own "language" Have to track of the transformations
88. scala-miniboxing.org @miniboxing Marking Changes Marking Changes Source Signatures Bytecode Source Signatures Bytecode Source Signatures Bytecode JVM scalac scalac scalac
89. scala-miniboxing.org @miniboxing Marking Changes Marking Changes Source Signatures Bytecode Source Signatures Bytecode Source Signatures Bytecode JVM scalac scalac scalac
90. scala-miniboxing.org @miniboxing Marking Changes Marking Changes Source Signatures Bytecode Source Signatures Bytecode Source Signatures Bytecode JVM scalac scalac scalac
91. scala-miniboxing.org @miniboxing Marking Changes Marking Changes • Keep track of changes to – Methods – Fields – Classes – Traits • Carry transformation info with types – Automatically annotate the code – The pickler phase stores them in signatures – Introduce conversions where necessary
92. scala-miniboxing.org @miniboxing Marking Changes Marking Changes
93. scala-miniboxing.org @miniboxing Marking Changes Marking Changes
94. scala-miniboxing.org @miniboxing Marking Changes Marking Changes
95. scala-miniboxing.org @miniboxing Marking Changes Marking Changes place a compiler phase here
96. scala-miniboxing.org @miniboxing Marking Changes Marking Changes def identityFun[@miniboxed T] = (t: T) => t typer
97. scala-miniboxing.org @miniboxing Marking Changes Marking Changes def identityFun[@miniboxed T] = (t: T) => t def identityFun[@miniboxed T]: Function1[T, T] = (t: T) => t typer interop-inject
98. scala-miniboxing.org @miniboxing Marking Changes Marking Changes def identityFun[@miniboxed T] = (t: T) => t def identityFun[@miniboxed T]: Function1[T, T] = (t: T) => t typer interop-inject @... def identityFun[@miniboxed T]: Function1[T, T] @mbFun = (t: T) => t pickler
99. scala-miniboxing.org @miniboxing Marking Changes Marking Changes def identityFun[@miniboxed T] = (t: T) => t def identityFun[@miniboxed T]: Function1[T, T] = (t: T) => t typer interop-inject @... def identityFun[@miniboxed T]: Function1[T, T] @mbFun = (t: T) => t Future compilation runs are aware of the change pickler
100. scala-miniboxing.org @miniboxing Conversions Conversions • What do to if – We have an MbFunction1 and – Callee expects Function1? • Conversions – Between the two cases – Functions defined in miniboxed code • Miniboxing-friendly and specialization-friendly – Functions defined in non-miniboxed code • Specialization-friendly • Need conversion Miniboxing friendly →
101. scala-miniboxing.org @miniboxing Conversions Conversions def identityFun[@miniboxed T] = Predef.identity typer
102. scala-miniboxing.org @miniboxing Conversions Conversions def identityFun[@miniboxed T] = Predef.identity def identityFun[@miniboxed T]: Function1[T, T] = Predef.identity[T] // : Function1[T, T] from classpath typer interop-inject
103. scala-miniboxing.org @miniboxing Conversions Conversions def identityFun[@miniboxed T] = Predef.identity def identityFun[@miniboxed T]: Function1[T, T] = Predef.identity[T] // : Function1[T, T] from classpath typer interop-inject @... def identityFun[@miniboxed T]: Function1[T, T] @mbFun = Predef.identity[T] // : Function1[T, T] no annotation interop-coerce
104. scala-miniboxing.org @miniboxing @... def identityFun[@miniboxed T]: Function1[T, T] @mbFun = toMbFun(Predef.identity[T]) // : Function1[T, T] @mbFun Conversions Conversions def identityFun[@miniboxed T] = Predef.identity def identityFun[@miniboxed T]: Function1[T, T] = Predef.identity[T] // : Function1[T, T] from classpath typer interop-inject @... def identityFun[@miniboxed T]: Function1[T, T] @mbFun = Predef.identity[T] // : Function1[T, T] no annotation interop-coerce
105. scala-miniboxing.org @miniboxing Conversions Conversions Conversions are introduced based on types See scala-miniboxing.org/ldl for details
106. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Dependencies Reverse deps Object model
107. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Dependencies Reverse deps Object model
108. scala-miniboxing.org @miniboxing Reverse Dependencies Reverse Dependencies Your library
109. scala-miniboxing.org @miniboxing Reverse Dependencies Reverse Dependencies Your library Scala stdlib Other library Other library dependencies
110. scala-miniboxing.org @miniboxing Reverse Dependencies Reverse Dependencies Your library Scala stdlib Other library Other library Other lib 1 Other lib 2 Other lib 3 dependencies reverse dependencies
111. scala-miniboxing.org @miniboxing Reverse Dependencies Reverse Dependencies Your library Scala stdlib Other library Other library Other lib 1 Other lib 2 Other lib 3 dependencies reverse dependencies
112. scala-miniboxing.org @miniboxing Reverse Dependencies Reverse Dependencies Your library Scala stdlib Other library Other library Other lib 1 Other lib 2 Other lib 3 dependencies reverse dependencies Libraries not compiled with the miniboxing plugin are not aware of the transformation → incorrect bytecode
113. scala-miniboxing.org @miniboxing Reverse Dependencies Reverse Dependencies $ scala Welcome to Scala version 2.11.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_101). Type in expressions to have them evaluated. Type :help for more information. scala> Test.identityFun(2) <console>:11: error: This method was compiled with the miniboxing plugin and can only be called by code also compiled with the miniboxing plugin (see scala-miniboxing.org/compatibility) [mbox=0.4-M8,scala=2.11.7] Test.identityFun(2) ^
114. scala-miniboxing.org @miniboxing Reverse Dependencies Reverse Dependencies def identityFun[@miniboxed T] = (t: T) => t def identityFun[@miniboxed T]: Function1[T, T] = (t: T) => t typer interop-inject @compileTimeOnly(...) def identityFun[@miniboxed T]: Function1[T, T] @mbFun = (t: T) => t pickler
115. scala-miniboxing.org @miniboxing Reverse Dependencies Reverse Dependencies def identityFun[@miniboxed T] = (t: T) => t def identityFun[@miniboxed T]: Function1[T, T] = (t: T) => t typer interop-inject @compileTimeOnly(...) def identityFun[@miniboxed T]: Function1[T, T] @mbFun = (t: T) => t Built into the Scala stdlib and recognized by scalac (checked by refchecks) pickler
116. scala-miniboxing.org @miniboxing Reverse Dependencies Reverse Dependencies miniboxing introduces annotation here
117. scala-miniboxing.org @miniboxing Reverse Dependencies Reverse Dependencies miniboxing introduces annotation here ... and removes it just before refchecks
118. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Dependencies Reverse deps Object model
119. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Dependencies Reverse deps Object model
120. scala-miniboxing.org @miniboxing Object Model Object Model trait IdentityFun { def identityFun[T]: T => T // = Function1 [T, T] }
121. scala-miniboxing.org @miniboxing Object Model Object Model trait IdentityFun { def identityFun[T]: T => T // = Function1 [T, T] } object MbIdentityFun extends IdentityFun { def identityFun[@miniboxed T]: T => T = (t: T) => t }
122. scala-miniboxing.org @miniboxing Object Model Object Model trait IdentityFun { def identityFun[T]: T => T // = Function1 [T, T] } object MbIdentityFun extends IdentityFun { def identityFun[@miniboxed T]: T => T = (t: T) => t } scala> MbIdentityFun.identityFun(2) <console>:11: error: ... scala> val id: IdentityFun = MbIdentityFun id: IdentityFun = MbIdentityFun$@23223dd8 scala> id.identityFun(3) res1: Int = 3
123. scala-miniboxing.org @miniboxing Object Model Object Model trait IdentityFun { def identityFun[T]: T => T // = Function1 [T, T] } object MbIdentityFun extends IdentityFun { def identityFun[@miniboxed T]: T => T = (t: T) => t } scala> MbIdentityFun.identityFun(2) <console>:11: error: ... scala> val id: IdentityFun = MbIdentityFun id: IdentityFun = MbIdentityFun$@23223dd8 scala> id.identityFun(3) res1: Int = 3 You can "hide" miniboxed code behind an interface
124. scala-miniboxing.org @miniboxing Object Model Object Model • Allows "hiding" miniboxed code – Under an erased interface (example) – Under a specialized interface • Pro: no dependency on the plugin downstream • Cons: have to write some glue code
125. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing Dependencies Reverse deps Object model
126. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing
127. scala-miniboxing.org @miniboxing RRBVector Experiment RRBVector Experiment • RRBVector is an immutable vector data structure – With constant-time split and merge (for parallel ops) • Idea by Phil Bagwell and Tiark Rompf • Implementation by Nicolas Stucki – 4 developer-weeks of work – Hand-tuned for maximum performance – Scaling almost linearly with the number of cores – Summing a vector is 2x as slow as summing an array • Presented at ICFP '15
128. scala-miniboxing.org @miniboxing RRBVector Experiment RRBVector Experiment • Questions: – How difficult is it to specialize RRBVector with miniboxing? – What are the speedups obtained by miniboxing? • Preparation: – Copied the Scala stdlib suppor necessary for RRBVector (3k LOC) – Eliminated the parallel execution support (3k 2k LOC) → – Prepared benchmarks • Subject: Milos Stojanovic – Master student working in the lab – Experienced with miniboxing – Never saw the RRBVector code base before
129. scala-miniboxing.org @miniboxing RRBVector Experiment RRBVector Experiment • It took 30 minutes to optimize the code base by following the miniboxing warnings → 0.3% of the development time Benchmark Microbenchmarks (5M elements) Macrobenchmark Builder map fold reverse* Least squares linear regression (5M points) Erased (seconds) 43.2 103.0 94.1 31.4 4864.6 Miniboxed (seconds) 22.9 60.4 42.1 35.3 1818.1 Speedup (ratio) 1.88x 1.71x 2.24x 0.89x 2.68x * reversing a vector does not perform any operations that could benefit from miniboxing.
130. scala-miniboxing.org @miniboxing RRBVector Experiment RRBVector Experiment • Used library features – MbFunction – MbArray – Tuples – Numeric – Ordering
131. scala-miniboxing.org @miniboxing RRBVector Experiment RRBVector Experiment • Used library features – MbFunction – MbArray – Tuples – Numeric – Ordering Impossible to cover today
132. scala-miniboxing.org @miniboxing
133. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing
134. scala-miniboxing.org @miniboxing Functions Transformation Experiment Conclusion Miniboxing
135. scala-miniboxing.org @miniboxing Miniboxed Library Miniboxed Library • Replaces deeply integrated Scala constructs – Preserve the syntactic sugar – No source code changes • Scalac/miniboxing does a lot of the work • Use cases – Miniboxing: performance – <your use case here>
136. scala-miniboxing.org @miniboxing scala-miniboxing.org Special thanks: Alexandru Nedelcu Milos Stojanovic Romain Beguet Nicolas Stucki Scala team @ EPFL