Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
The Value of Being Lazy
Search
Erik Berlin
November 24, 2015
Programming
3
740
The Value of Being Lazy
…or How I Made OpenStruct 10X Faster
Presented at Rails Israel 2015.
Erik Berlin
November 24, 2015
Tweet
Share
More Decks by Erik Berlin
See All by Erik Berlin
Enumerator::Lazy
sferik
2
540
Ruby Trivia 3
sferik
0
680
Ruby Trivia 2
sferik
0
720
Ruby Trivia
sferik
2
1.3k
💀 Symbols
sferik
5
1.9k
Content Negotiation for REST APIs
sferik
8
960
Writing Fast Ruby
sferik
628
61k
Mutation Testing with Mutant
sferik
5
1.1k
Other Decks in Programming
See All in Programming
Optimizing JRuby 10
headius
0
300
Do Dumb Things
mitsuhiko
0
430
Compose Hot Reload is here, stop re-launching your apps! (Android Makers 2025)
zsmb
1
500
海外のアプリで見かけたかっこいいTransitionを真似てみる
shogotakasaki
1
170
アプリを起動せずにアプリを開発して品質と生産性を上げる
ishkawa
0
2.7k
AWS で実現する安全な AI エージェントの作り方 〜 Bedrock Engineer の実装例を添えて 〜 / how-to-build-secure-ai-agents
gawa
8
790
Enterprise Web App. Development (1): Build Tool Training Ver. 5
knakagawa
1
110
データベースエンジニアの仕事を楽にする。PgAssistantの紹介
nnaka2992
9
4.5k
Being an ethical software engineer
xgouchet
PRO
0
210
マルチアカウント環境での、そこまでがんばらない RI/SP 運用設計
wa6sn
0
720
リアクティブシステムの変遷から理解するalien-signals / Learning alien-signals from the evolution of reactive systems
yamanoku
3
1.2k
趣味全開のAITuber開発
kokushin
0
200
Featured
See All Featured
Fashionably flexible responsive web design (full day workshop)
malarkey
407
66k
Distributed Sagas: A Protocol for Coordinating Microservices
caitiem20
331
21k
実際に使うSQLの書き方 徹底解説 / pgcon21j-tutorial
soudai
178
53k
Art, The Web, and Tiny UX
lynnandtonic
298
20k
The Art of Programming - Codeland 2020
erikaheidi
53
13k
Product Roadmaps are Hard
iamctodd
PRO
52
11k
KATA
mclloyd
29
14k
Designing for humans not robots
tammielis
252
25k
The Language of Interfaces
destraynor
157
24k
Build your cross-platform service in a week with App Engine
jlugia
229
18k
The Art of Delivering Value - GDevCon NA Keynote
reverentgeek
13
1.4k
Designing for Performance
lara
608
69k
Transcript
THE VALUE OF BEING LAZY or How I Made OpenStruct
10X Faster Erik Michaels-Ober @sferik
In Ruby, everything is an object. ∀ thing thing.is_a?(Object) #=>
true
In Ruby, every object has a class. ∀ object object.respond_to?(:class)
#=> true
In Ruby, every class has a class. ∴ Object.respond_to?(:class) #=>
true Object.class #=> Class
You can use classes to create new objects: object =
Object.new object.class #=> Object
You can use classes to create new classes: klass =
Class.new klass.class #=> Class
Usually, we create classes like this: class Point attr_accessor :x,
:y def initialize(x, y) @x, @y = x, y end end
You can replace such simple classes with structs: Point =
Struct.new(:x, :y)
OpenStruct requires even less definition: point = OpenStruct.new point.x =
1 point.y = 2
In this way, OpenStruct is similar to Hash: point =
Hash.new point[:x] = 1 point[:y] = 2
You can even initialize OpenStruct with a Hash: point =
OpenStruct.new(x: 1, y: 2) point.x #=> 1 point.y #=> 2
So why use OpenStruct instead of Hash?
Test double validator = OpenStruct.new expect(validator).to receive(:validate) code = PostalCode.new("94102",
validator) code.valid?
API response user = OpenStruct.new(JSON.parse(response)) user.name #=> Erik
Configuration object def options opts = OpenStruct.new yield opts opts
end
So OpenStruct is useful…but slow.
None
Steps to optimize code 1. Complain that code is slow
on Twitter 2. ??? 3. Profit
Actual steps to optimize code 1. Benchmark 2. Read code
3. Profit
Actual steps to optimize code 1. Benchmark 2. Read code
3. Profit
require "benchmark/ips" Point = Struct.new(:x, :y) def struct Point.new(0, 1)
end def ostruct OpenStruct.new(x: 0, y: 1) end Benchmark.ips do |x| x.report("ostruct") { ostruct } x.report("struct") { struct } end
Comparison: struct: 2927800.2 i/s ostruct: 84741.1 i/s - 34.55x slower
Actual steps to optimize code 1. Benchmark 2. Read code
3. Profit
def initialize(hash = nil) @table = {} if hash hash.each_pair
do |k, v| k = k.to_sym @table[k] = v new_ostruct_member(k) end end end
def new_ostruct_member(name) name = name.to_sym unless respond_to?(name) define_singleton_method(name) { @table[name]
} define_singleton_method("#{name}=") { |x| @table[name] = x } end name end
def method_missing(mid, *args) len = args.length if mname = mid[/.*(?==\z)/m]
@table[new_ostruct_member(mname)] = args[0] elsif len == 0 if @table.key?(mid) new_ostruct_member(mid) @table[mid] end end end
def initialize(hash = nil) @table = {} if hash hash.each_pair
do |k, v| k = k.to_sym @table[k] = v new_ostruct_member(k) end end end
Before: struct: 2927800.2 i/s ostruct: 84741.1 i/s - 34.55x slower
After: struct: 2927800.2 i/s ostruct: 940170.4 i/s - 3.11x slower
None
None
git log --reverse lib/ostruct.rb
None
Lazy evaluation
Enumerator::Lazy
lazy_integers = (1..Float::INFINITY).lazy lazy_integers.collect { |x| x ** 2 }.
select { |x| x.even? }. reject { |x| x < 1000 }. first(5) #=> [1024, 1156, 1296, 1444, 1600]
require "prime" lazy_primes = Prime.lazy lazy_primes.select { |x| (x -
2).prime? }. collect { |x| [x - 2, x] }. first(5) #=> [[3, 5], [5, 7], [11, 13], [17, 19], [29, 31]]
module Enumerable def repeat_after_first unless block_given? return to_enum(__method__) { size
* 2 - 1 if size } end each.with_index do |*val, index| index == 0 ? yield *val : 2.times { yield *val } end end end
require "prime" lazy_primes = Prime.lazy lazy_primes.repeat_after_first. each_slice(2). select { |x,
y| x + 2 == y }. first(5) #=> [[3, 5], [5, 7], [11, 13], [17, 19], [29, 31]]
require "date" lazy_dates = (Date.today..Date.new(9999)).lazy lazy_dates.select { |d| d.day ==
13 }. select { |d| d.friday? }. first(10)
lazy_file = File.readlines("/path/to/file").lazy lazy_file.detect { |x| x =~ /regexp/ }
Being lazy is efficient.
Being lazy is elegant.
Thanks to: Zachary Scott ROSS Conf Rails Israel
Thank you