RailsConf 2016 Keynote - Speaker Deck

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How people build software ! " Make Rails Great Again A @tenderlove Guide to Things

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How people build software ! HELLO!!!! 2 !

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How people build software ! Aaron Patterson 3 !

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How people build software ! @tenderlove 4 !

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How people build software ! Ruby Core Team Rails Core Team 6 !

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How people build software ! Ruby Security Team Rails Security Team 7 !

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How people build software ! PGP Fingerprint: 4CE9 1B75 A798 28E8 6B1A A8BB 9531 70BC B4FF AFC6 8 !

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How people build software ! #2 Committer 9 !

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How people build software ! GitHub 11 !

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How people build software ! Le Git 12 !

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How people build software ! GitHug 13 !

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Plain old slides

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Brought to you by @ihavenotea

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I have stickers of my cats

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My Job at GitHub

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GitHub: How people build software

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Bringing GitHub Application Development to Everyone

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Rails Core Develompent

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Ruby Core Development

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Buy our products!

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My Career Goals

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I wanted to get rich.

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Why?

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So that I could do what I want. (Which is making Rails great again)

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Become a Cog

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I want to be a cog!

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New in Rails 5

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Rails is in it’s Prime 5

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No more XML situps

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JSON burpees

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Threading

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Race Condition VROOOOM!!!!

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Le Mans is just Nascar for Europe Follow @ juliancheal today! (He gave me this joke) Advertisement:

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Ruby Drama

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I am extremely angry at Jeremy

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Friday, April 22, 2016 7:57 pm

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JEREMY!!!

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$5 footlong

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WHAT EVEN IS THIS?

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Ruby on Rails The mainstream }The Surplus of Slides

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I ❤ u JD!

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Major Changes in ActiveRecord

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I want to talk about SQL

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So I’ve prepared a statement Follow @ kerrizor today! ❤ Advertisement:

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ApplicationRecord

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Appealing to Startups

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Application Generation [aaron@TC rails (master)]$ ruby railties/exe/rails new ~/git/omglolwut2 --dev --skip-bundle create create README.md create Rakefile create config.ru create .gitignore create Gemfile create app create app/assets/config/manifest.js create app/assets/javascripts/application.js create app/assets/javascripts/cable.js create app/assets/stylesheets/application.css create app/channels/application_cable/channel.rb create app/channels/application_cable/connection.rb create app/controllers/application_controller.rb create app/helpers/application_helper.rb create app/jobs/application_job.rb create app/mailers/application_mailer.rb create app/models/application_record.rb create app/models/business.rb create app/views/layouts/application.html.erb create app/views/layouts/mailer.html.erb create app/views/layouts/mailer.text.erb create app/assets/images/.keep create app/assets/javascripts/channels create app/assets/javascripts/channels/.keep create app/controllers/concerns/.keep create app/models/concerns/.keep create bin create bin/bundle create bin/rails create bin/rake create bin/setup create bin/update create config create config/routes.rb create config/application.rb create config/environment.rb create config/secrets.yml create config/cable.yml create config/puma.rb om glolwut2

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Application Generation create app/controllers/application_controller.rb create app/helpers/application_helper.rb create app/jobs/application_job.rb create app/mailers/application_mailer.rb create app/models/application_record.rb create app/models/business.rb create app/views/layouts/application.html.erb create app/views/layouts/mailer.html.erb

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Business Model [aaron@TC rails (master)]$ cd ~/git/omglolwut2 [aaron@TC omglolwut2]$ cat app/models/business.rb class Business < ApplicationRecord # Business model end [aaron@TC omglolwut2]$

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This is a HackerNews compliant business model

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Surprises!

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PHP templates

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We need to go further

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Lets get down to business

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What have you done for me lately?

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Yes, but what have you done for me *lately*?

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Performance

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SURPRISE!!! GitHub: You can put code there! Advertisement:

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I ❤ Performance

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Topics Boot Time Performance Run Time Performance Memory Efﬁciency

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Performance is always about tradeoffs

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Memory for speed

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Concurrency for memory

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Complexity for memory

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Performance is never free

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Always understand your constraints.

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Boot Time Performance leftpad-ng.js: for all your padding needs, but only on the left side Advertisement:

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bundle exec rails s RubyGems Bundler Rails Rails

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bundle exec rails s RubyGems Bundler Rails Rails

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Speeding up Ruby speeds up everything.

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But that doesn’t mean we should write slow code.

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Two Optimizations Ruby (sort of) RubyGems

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Run an empty program [aaron@TC ~]$ ruby -v ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-darwin15] [aaron@TC ~]$ time ruby -e' ' real 0m0.101s user 0m0.061s sys 0m0.032s OMG RUBY IS SLOW

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Without RubyGems [aaron@TC ~]$ ruby -v ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-darwin15] [aaron@TC ~]$ time ruby -e' ' real 0m0.101s user 0m0.061s sys 0m0.032s [aaron@TC ~]$ time ruby --disable-gems -e' ' real 0m0.051s user 0m0.022s sys 0m0.023s

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Measurement by Elimination

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Placing blame is difﬁcult git blame: for all your blame placing needs Advertisement:

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gem_prelude.rb

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Gem Prelude if defined?(Gem) require 'rubygems.rb' begin require 'did_you_mean' rescue LoadError end if defined?(DidYouMean) end Load Rubygems

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Why load RubyGems? [aaron@TC ~]$ ruby -e'require "rubygems"; require "rails"' [aaron@TC ~]$ ruby -e'require "rails"' Bad old days of Ruby 1.8 Ruby 1.9+

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Gem Prelude if defined?(Gem) require 'rubygems.rb' begin require 'did_you_mean' rescue LoadError end if defined?(DidYouMean) end Load Rubygems did_you_mean New in Ruby 2.3!

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Did you mean? [aaron@TC ~]$ ruby -e'Object.new.object_ip' -e:1:in `': undefined method `object_ip' for # (NoMethodError) Did you mean? object_id [aaron@TC ~]$ I see you’re trying to call a method!

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did_you_mean is a gem

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Gem Prelude if defined?(Gem) require 'rubygems.rb' begin require 'did_you_mean' rescue LoadError end if defined?(DidYouMean) end did_you_mean

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# RubyGems's require: TL;DR alias :original_require :require def require file original_require file rescue LoadError found_gem = all_gems.find do |gem| gem.contains?(file) || gem.contains?(file + ".rb") || gem.contains?(file + ".so") # .bundle on OS X, .dll on Windows end if found_gem found_gem.activate # mutates $LOAD_PATH original_require file else raise "idk lol" end end RubyGems’ Require O(3N) or just O(N)

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The more gems installed, the slower `require` gets

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The more gems installed, the slower `ruby` gets.

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Watch the O(N) $ sudo dtrace -q -n \ 'syscall::stat*:entry { printf("%s\n", copyinstr(arg0)); }' \ -c`rbenv which ruby`" -e '\ '"

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Run it! [aaron@TC ~]$ sudo dtrace -q -n 'syscall::stat*:entry { printf("%s\n", copyinstr(arg0)); }' -c`rbenv which ruby`" -e '\ '" | wc -l 298 [aaron@TC ~]$ sudo dtrace -q -n 'syscall::stat*:entry { printf("%s\n", copyinstr(arg0)); }' -c`rbenv which ruby`" -- disable-did_you_mean -e '\ '" | wc -l 12 [aaron@TC ~]$ sudo dtrace -q -n 'syscall::stat*:entry { printf("%s\n", copyinstr(arg0)); }' -c`rbenv which ruby`" -- disable-gems -e '\ '" | wc -l 5 [aaron@TC ~]$ With RubyGems Without did_you_mean Without Both

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File Stats actioncable-5.0.0.beta2/lib/did_you_mean actioncable-5.0.0.beta2/lib/did_you_mean.rb actioncable-5.0.0.beta2/lib/did_you_mean.bundle actionmailer-5.0.0.beta2/lib/did_you_mean actionmailer-5.0.0.beta2/lib/did_you_mean.rb actionmailer-5.0.0.beta2/lib/did_you_mean.bundle actionpack-5.0.0.beta2/lib/did_you_mean actionpack-5.0.0.beta2/lib/did_you_mean.rb actionpack-5.0.0.beta2/lib/did_you_mean.bundle actionview-5.0.0.beta2/lib/did_you_mean actionview-5.0.0.beta2/lib/did_you_mean.rb actionview-5.0.0.beta2/lib/did_you_mean.bundle activejob-5.0.0.beta2/lib/did_you_mean activejob-5.0.0.beta2/lib/did_you_mean.rb activejob-5.0.0.beta2/lib/did_you_mean.bundle

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GOOD NEWS EVERYONE

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"d" is pretty early in the alphabet!

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To speed up Rails, let us rename it to AAARails

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Improvement

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Use `gem` $ cat test.rb require "did_you_mean" $ sudo sh count_syscalls.sh | wc -l 299 $ cat test.rb gem "did_you_mean" require "did_you_mean" $ sudo sh count_syscalls.sh | wc -l 16 Bare `require` `gem` + `require`

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Why this is faster: def gem gem_name spec = load_specfile(gem_name + ".gemspec") spec.activate # mutates the load path end # RubyGems's require: TL;DR alias :original_require :require def require file original_require file rescue LoadError found_gem = all_gems.find do |gem| gem.contains?(file) || gem.contains?(file + ".rb") || gem.contains?(file + ".so") # .dylib on OS X, .dll on Windows end if found_gem found_gem.activate # mutates $LOAD_PATH original_require file else raise "idk lol" end end O(1) O(1)* *Not actually O(1)

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Fix gem_prelude.rb diff --git a/gem_prelude.rb b/gem_prelude.rb index 3f171d1..be9c419 100644 --- a/gem_prelude.rb +++ b/gem_prelude.rb @@ -1,7 +1,8 @@ if defined?(Gem) require 'rubygems.rb' begin + gem 'did_you_mean' require 'did_you_mean' - rescue LoadError + rescue Gem::LoadError, LoadError end if defined?(DidYouMean) end

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Bare Require: O(N) Gem + Require: O(1)

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Tradeoffs: Complexity for Speed

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Complexity does have overhead

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bundle exec rails s RubyGems Bundler Rails Rails Probably want the bundler gem

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`bundle` before RG 2.5.2 [aaron@TC ~]$ tail -3 `rbenv which bundler` gem 'bundler', version load Gem.bin_path('bundler', 'bundler', version) [aaron@TC ~]$ O(1)

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RG >= 2.5.2, < 2.6.2 [aaron@TC ~]$ tail -3 `rbenv which bundler` end load Gem.bin_path('bundler', 'bundler', version) [aaron@TC ~]$ (N)

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bundle exec rails s RubyGems Bundler Rails Rails

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New Technology!!!!* *Not actually new

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Startup Time 12% 13% 34% 41% Compilation Execution Searching GC These Are Not Actual Times

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How does GC impact? require 'benchmark/ips' # GC.disable # Uncomment to measure GC Benchmark.ips do |x| x.report("something") do call_some_method end end

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Startup Time 12% 13% 34% 41% Compilation Execution Searching GC These Are Not Actual Times

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https://github.com/byroot/ bootscale This link brought to you by GitHub dot com Advertisement:

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Startup Time 13% 39% 47% Compilation Execution GC These Are Not Actual Times

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Startup Time 46% 54% Compilation Execution These Are Not Actual Times

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Lets tackle compilation!

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Go to @_ko1’s talk

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that was yesterday…

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Program Flow Source Code Byte Code Execution Cache this!

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Program Flow Source Code Byte Code Execution Read Byte Code from File Byte Code Execution

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Compilation Script input_file = ARGV[0] output_file = input_file + "c" insns = RubyVM::InstructionSequence.compile_file input_file File.binwrite output_file, insns.to_binary New in Ruby 2.3!

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Compilation Example $ cat hello.rb class Hello def hello! puts "hello" end end $ ruby compile.rb hello.rb $ cat hello.rbc YARB? LX?x86_64-darwin15*0*3 +3DD*???????**0*3 $t|????????||T? Ehello!EhelloEHelloEputsEcore#define_methodx????8Qj?

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1st half is done

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Load & Execute Byte Code compiled_file = ARGV[0] binary_data = File.binread compiled_file insns = RubyVM::InstructionSequence.load_from_binary binary_data insns.eval Hello.new.hello! New in Ruby 2.3!

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Run it $ ruby load_compiled_file.rb hello.rbc hello

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2nd half is done

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100% done, but Rails isn’t faster

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I always give 110%

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Integrating with `require`

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Require Process # a.rb require 'b' # b.rb require 'c' # c.rb require 'b'

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Dependencies a.rb b.rb c.rb

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Require Process Start to require 'b' Acquire lock for "b" Start to require 'c' Acquire lock for "c" Try to require 'b' Already locked for "b" Finish require 'c' Finish require 'b' Release lock for "c" Release lock for "b"

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There are many rules, and I don’t want to ﬁgure them out.

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Load File Hook set_load_required_file_func ->(full_file) { if can_handle?(full_file) # do something true else # do something else false end } require 'foo' I want foo.rb! /path/to/foo.rb

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https://github.com/tenderlove/ ruby/tree/binload ADVERTISING!!

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Load Compiled Code if ENV['COMP'] set_load_required_file_func ->(full_path) { fname = full_path + "o" if File.exist? fname insns = RubyVM::InstructionSequence.load_from_binary File.binread fname insns.eval true else insns = RubyVM::InstructionSequence.compile_file full_path File.binwrite fname, insns.to_binary false end } end https://gist.github.com/tenderlove/f6f4189db2eb748802b21a8b4fd52c99

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Compiled vs Non-Compiled [aaron@TC omglolwut (master)]$ time RUBYOPT='-I. -rx' bin/rails db:migrate real 0m1.804s user 0m1.487s sys 0m0.414s [aaron@TC omglolwut (master)]$ time COMP=1 RUBYOPT='-I. -rx' bin/rails db:migrate real 0m1.273s user 0m1.002s sys 0m0.374s Before (not compiled) After (compiled)

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~30% faster Try mechanical keyboards today! Advertisement:

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The more code, the bigger the impact.

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Future Work Upstream new callback Compile code on `gem install` Cache invalidation If you like "cache invalidation", try "naming things"! Advertisement:

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Runtime Performance

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Polymorphic Inline Caching

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Inline Caching class Hello def bar; end end def foo(object) object.bar end foo Hello.new foo Hello.new `object` is Hello, where is foo? `object` is Hello, I know where foo is. HIT! Cache Contents Key Value [Hello, foo] method source

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Inline Caching class Hello def bar; end end class World def bar; end end def foo(object) object.bar end foo Hello.new foo World.new `object` is Hello, where is foo? MISS `object` is World, where is foo? MISS Cache Contents Key Value [Hello, foo] method source

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Cache size: 1

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Monomorphic Inline Cache

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Cache size: 2 class Hello def bar; end end class World def bar; end end def foo(object) object.bar end foo Hello.new foo World.new foo Hello.new foo World.new òbject` is Hello, where is foo? MISS òbject` is World, where is foo? MISS òbject` is Hello, I know foo. HIT òbject` is World, I know foo. HIT Cache Contents Key Value [Hello, foo] method source [World, foo] method source

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Cache size 2 (or more)

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Polymorphic Inline Cachine

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Pays off when many call sites "see" many types.

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Implemented here: https://github.com/tenderlove/ruby/tree/PIC_expand

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TL;DR: Didn’t help

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~3% of calls saw 2 types Test App: https://github.com/manageiq/manageiq Current Company Previous Company

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Tradeoff: Complexity / Memory For Speed

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Call site with 1600 types

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Class Creation Code class Hello end def foo(object) object.bar end 2.times { hello = Hello.new hello.instance_eval do end } Creates a new subclass of Hello Always sees an anonymous class

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What class is this? class Hello end var = Hello.new Ancestors BasicObject Kernel Object Hello #

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Singleton Uses • instance_eval • singleton_class • def my_obj.some_method; end

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Given "I’m a Rails Dev" When "Presented with this info" Then "Why should I care?" Brought to you by rspec-given. It’s a Given! Advertisement:

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Some libraries do this

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Don’t write code like that

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If you think you have to

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Just don’t. This slide brought to you by singleton classes Advertisement:

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If you really really really must Brought to you by eigenclasses Advertisement:

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We can speed it up.

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Singleton classes with no new methods are equal to the superclass Your ad here! Contact @tenderlove for details Advertisement:

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Patch to Copy $ git diff trunk class.c diff --git a/class.c b/class.c index 0261838..65428be 100644 --- a/class.c +++ b/class.c @@ -1591,7 +1591,9 @@ singleton_class_of(VALUE obj) klass = RBASIC(obj)->klass; if (!(FL_TEST(klass, FL_SINGLETON) && rb_ivar_get(klass, id_attached) == obj)) { + rb_serial_t serial = RCLASS_SERIAL(klass); klass = rb_make_metaclass(obj, klass); + RCLASS_SERIAL(klass) = serial; } if (OBJ_TAINTED(obj)) { https://github.com/tenderlove/ruby/tree/singleton-serial

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Benchmark class C1 def m; 1; end end o1 = C1.new o2 = C1.new o2.singleton_class i = 0 while i<6_000_000 # benchmark loop 2 o = (i % 2 == 0) ? o1 : o2 o.m; o.m; o.m; o.m; o.m; o.m; o.m; o.m i += 1 end

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Run it! [aaron@TC ruby (trunk)]$ time ./ruby benchmark/ bm_vm2_poly_singleton.rb real 0m2.510s user 0m2.453s sys 0m0.024s [aaron@TC ruby (singleton-serial)]$ time ./ruby benchmark/ bm_vm2_poly_singleton.rb real 0m1.380s user 0m1.319s sys 0m0.020s

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45% faster!

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Trade off: Complexity for Speed

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Memory Efﬁciency

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Copy on Write (a.k.a. CoW) Milk! It’s what’s for dinner Advertisement:

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Heap Layout Optimizations

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Copy on Write Parent Process Child Process Child Process Memory

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Copy on Write Parent Process Child Process Child Process Memory Memory

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"Page Fault"

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OS copies some of the memory

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Ruby Memory Layout Pages Object Object Object Object Object Object Object Object Object Object Object Object

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GC Happens Pages Object Object Object Object Object Object Object Object Object Object FREE! FREE! FREE! FREE! Object Object

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Objects Don’t Move

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Swiss Cheese Memory Pages Object FREE! FREE! Object FREE! FREE! Object Object Object Object Object Object

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CoW wastefulness Pages Object FREE! FREE! Object FREE! FREE! Object Object Object Object Object Object Object Parent Child Copied to Child

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OS Page Size 4k Ruby Page Size 16k Ruby Object Size 40 bytes

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1 Ruby Page: ~400 Objects

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1 Ruby Page: 4 OS Pages

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1 OS Page: ~100 Ruby Objects

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We’re probably copying too many objects. Try JRuby: it’s Ruby with a J Advertisement:

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This only impacts Ruby code that forks.

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Unicorn Ugh. This is the web server we use.

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Sideways Ruby Page

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Sideways Ruby Page Imaginary Ruby Page (Slab)

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Pages dedicated to "probably old" objects

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What are "probably old" objects?

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Probably old class Foo end module Bar end BAZ = "OMGOMG!!"

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Tradeoffs?

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Complexity for memory?

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How complex?

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How much memory?

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Tools for introspection

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github.com/tenderlove/heapfrag Sponsored link:

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No content

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Wrap it up!!

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5 lessons

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What do I value? What should I measure How can I measure it Does it provide shareholder value?

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1. What do I value?

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2. What should I measure?

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3. How can I measure it?

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4. Does it provide shareholder value? ActionCable: it’s a thing!! Advertisement: