Ruby VM Method Caching

2.0 Ruby VM Method Caching Friday, April 19, 13

Friday, April 19, 13

tl;dr Friday, April 19, 13

•Method lookup é caro em OO tl;dr Friday, April 19,
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•Method lookup é caro em OO •O que expira o
cache do MRI tl;dr Friday, April 19, 13

•Method lookup é caro em OO •O que expira o
cache do MRI •Object#extend e o desempenho do MRI tl;dr Friday, April 19, 13

method caching Friday, April 19, 13

method caching class Foo def bar end end
1_000_000.times do foo = Foo.new foo.bar end Friday, April 19, 13

1_000_000.times do foo = Foo.new foo.bar end callsite Friday, April 19, 13

1_000_000.times do foo = Foo.new foo.bar end callsite callsite Friday, April 19, 13

1_000_000.times do foo = Foo.new foo.bar end callsite callsite cada chamada de método é um novo callsite Friday, April 19, 13

method lookup Friday, April 19, 13

method lookup class Foo def bar end end
class Man < Foo; end class Choo < Man;end class Zoo < Choo;end Zoo.new.bar Friday, April 19, 13

class Man < Foo; end class Choo < Man;end class Zoo < Choo;end Zoo.new.bar • method lookup é caro no Ruby (tree of hashes with methods) Friday, April 19, 13

class Man < Foo; end class Choo < Man;end class Zoo < Choo;end Zoo.new.bar • method lookup é caro no Ruby (tree of hashes with methods) • a cada novo callsite, o Ruby cacheia as instruções do método Friday, April 19, 13

class Man < Foo; end class Choo < Man;end class Zoo < Choo;end Zoo.new.bar • method lookup é caro no Ruby (tree of hashes with methods) • a cada novo callsite, o Ruby cacheia as instruções do método • inline caching: perto das instruções do callsite Friday, April 19, 13

inline caching Friday, April 19, 13

inline caching •veio do SmallTalk Friday, April 19, 13

inline caching •veio do SmallTalk •monomórﬁco e polimórﬁco Friday, April
19, 13

inline caching •veio do SmallTalk •monomórﬁco e polimórﬁco •amplamente usado
(JavaScript) Friday, April 19, 13

inline caching no MRI Friday, April 19, 13

inline caching no MRI •expiry global (ruby_vm_global_state_version) Friday, April
19, 13

inline caching no MRI •expiry global (ruby_vm_global_state_version) •monomórﬁco Friday,
April 19, 13

inline caching no MRI •expiry global (ruby_vm_global_state_version) •monomórﬁco •performance
depende do código (YMMV) Friday, April 19, 13

inline caching no MRI •expiry global (ruby_vm_global_state_version) •monomórﬁco •performance
depende do código (YMMV) •quebra o DCI (rubydrama): domain model (data), use cases (context), interacUon Friday, April 19, 13

inline caching no MRI key: “klass” + ruby_vm_global_state_version value: instruções
da vm Friday, April 19, 13

o que expira o cache do MRI Friday, April 19,
13

o que expira o cache do MRI def foo end
o = Object.new def o.singleton end Friday, April 19, 13

o que expira o cache do MRI def foo end
o = Object.new def o.singleton end deﬁnir novos métodos num objeto Friday, April 19, 13

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o que expira o cache do MRI alias say puts
Kernel.send :alias_method, :say, :puts Friday, April 19, 13

o que expira o cache do MRI deﬁnir/undef aliases alias
say puts Kernel.send :alias_method, :say, :puts Friday, April 19, 13

say puts Kernel.send :alias_method, :say, :puts FOO = "bar" Object.const_set :FOO, "bar" Object.send :remove_const, :Kernel Friday, April 19, 13

say puts Kernel.send :alias_method, :say, :puts FOO = "bar" Object.const_set :FOO, "bar" Object.send :remove_const, :Kernel deﬁnir/undef CONSTs Friday, April 19, 13

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o que expira o cache do MRI class A #
definir classe end Friday, April 19, 13

definir classe end class << "Hello World" # criar singleton end Friday, April 19, 13

definir classe end module B # definir módulo end class << "Hello World" # criar singleton end Friday, April 19, 13

definir classe end module B # definir módulo end class Object # reabrir objeto (monkeypatch) end class << "Hello World" # criar singleton end Friday, April 19, 13

definir classe end module B # definir módulo end class Object # reabrir objeto (monkeypatch) end class << "Hello World" # criar singleton end "Hello World".extend(B) # criar singleton Friday, April 19, 13

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o que expira o cache do MRI GC.start # ligar
o Garbage Collector Friday, April 19, 13

o que expira o cache do MRI GC.start # ligar
o Garbage Collector OpenStruct.new(a: 1, b: 2) # openstructs Friday, April 19, 13

object#extend Friday, April 19, 13

object#extend •todo objeto no Ruby tem sua eigenclass Friday, April
19, 13

object#extend •todo objeto no Ruby tem sua eigenclass •“eigen” -‐
“o meu puro eu” em alemão Friday, April 19, 13

“o meu puro eu” em alemão •o Ruby cria eigenclasses em lazy mode Friday, April 19, 13

“o meu puro eu” em alemão •o Ruby cria eigenclasses em lazy mode •cada vez que um objeto ganha um método diferente da sua classe, sua eigenclass é criada Friday, April 19, 13

“o meu puro eu” em alemão •o Ruby cria eigenclasses em lazy mode •cada vez que um objeto ganha um método diferente da sua classe, sua eigenclass é criada •classes são sua própria eigenclass Friday, April 19, 13

object#extend class Dog def bark! puts
“woof” end end arlindo = Dog.new def arlindo.weird_bark! puts “woofaaafz” end normal_dog = Dog.new normal_dog > Dog > Object > BasicObject arlindo > eigenclass > Dog > Object > BasicObject Friday, April 19, 13

object#extend normal_dog.class > Dog Friday, April 19,
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object#extend normal_dog.class > Dog arlindo.class > Dog
Friday, April 19, 13

object#extend normal_dog.class > Dog arlindo.class > Dog
o Ruby esconde a eigenclass e só muda o ponteiro da “klass” para a nova classe Friday, April 19, 13

object#extend •Ruby tem instruções oUmizadas para alguns métodos: +,
-‐, [], []=, size, empty? Friday, April 19, 13

-‐, [], []=, size, empty? •Array, Hashes, operações básicas Friday, April 19, 13

-‐, [], []=, size, empty? •Array, Hashes, operações básicas •Se existe uma eigenclass, o Ruby usa as instruções não oUmizadas (até 100% mais lento, YMMV) Friday, April 19, 13

referências Friday, April 19, 13

referências hhp://jamesgolick.com/2013/4/14/mris-‐method-‐caches.html Friday, April 19, 13

referências hhp://jamesgolick.com/2013/4/14/mris-‐method-‐caches.html hhp://charlie.bz/blog/things-‐that-‐clear-‐rubys-‐method-‐cache Friday, April 19, 13

referências hhp://jamesgolick.com/2013/4/14/mris-‐method-‐caches.html hhp://charlie.bz/blog/things-‐that-‐clear-‐rubys-‐method-‐cache hhp://charlie.bz/blog/why-‐do-‐singleton-‐methods-‐make-‐ruby-‐slow Friday, April 19, 13

referências hhp://jamesgolick.com/2013/4/14/mris-‐method-‐caches.html hhp://charlie.bz/blog/things-‐that-‐clear-‐rubys-‐method-‐cache hhp://charlie.bz/blog/why-‐do-‐singleton-‐methods-‐make-‐ruby-‐slow hhp://blog.headius.com/2012/09/avoiding-‐hash-‐lookups-‐in-‐ruby.html Friday, April 19, 13

referências hhp://jamesgolick.com/2013/4/14/mris-‐method-‐caches.html hhp://charlie.bz/blog/things-‐that-‐clear-‐rubys-‐method-‐cache hhp://charlie.bz/blog/why-‐do-‐singleton-‐methods-‐make-‐ruby-‐slow hhp://blog.headius.com/2012/09/avoiding-‐hash-‐lookups-‐in-‐ruby.html hhp://madebydna.com/all/code/2011/06/24/eigenclasses-‐demysUﬁed.html Friday, April 19, 13

referências hhp://jamesgolick.com/2013/4/14/mris-‐method-‐caches.html hhp://charlie.bz/blog/things-‐that-‐clear-‐rubys-‐method-‐cache hhp://charlie.bz/blog/why-‐do-‐singleton-‐methods-‐make-‐ruby-‐slow hhp://blog.headius.com/2012/09/avoiding-‐hash-‐lookups-‐in-‐ruby.html hhp://madebydna.com/all/code/2011/06/24/eigenclasses-‐demysUﬁed.html hhp://en.wikipedia.org/wiki/Inline_caching Friday, April 19,
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Ruby VM Method Caching

Ruby VM Method Caching

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