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Levels of Optimization
Design
Source
Build
Compile
Runtime
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Levels of Optimization
Design
Source
Build
Compile
Runtime
Architecture and algorithms (e.g. n + 1 queries)
Writing fast Ruby
Setting build flags (e.g. ./configure)
mrbc, jrubyc, rbx compile
Thanks Matz & Koichi (e.g. RUBY_GC_MALLOC_LIMIT)
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Benchmark
require ‘benchmark'
n = 50
Benchmark.bm do |x|
x.report { n.times { fast } }
x.report { n.times { slow } }
end
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Benchmark
require ‘benchmark'
n = 50_000
Benchmark.bm do |x|
x.report { n.times { fast } }
x.report { n.times { slow } }
end
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Benchmark IPS
require 'benchmark/ips'
Benchmark.ips do |x|
x.report('fast') { fast }
x.report('slow') { slow }
end
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Goals
Source
Significant
Easy
Happy
Optimize at the code level
At least 12% improvement
Code should be easier to read
High quality Ruby
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Proc#call versus yield
def slow(&block)
block.call
end
def fast
yield
end
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Results
slow 950950.6 (±14.0%) i/s
fast 5508226.3 (±15.5%) i/s
Over 5X faster!
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Proc#call versus yield
def slow
Proc.new.call
end
def fast
yield
end
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Block versus Symbol#to_proc
(1..100).map { |i| i.to_s }
(1..100).map(&:to_s)
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Results
slow 47524.3 (±7.6%) i/s
fast 56823.2 (±7.2%) i/s
20% faster!
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Enumerable#map and Array#flatten
versus Enumerable#flat_map
enum.map do
# do something
end.flatten(1)
enum.flat_map do
# do something
end
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Results
slow 12348.2 (±9.0%) i/s
fast 56647.8 (±7.2%) i/s
Over 4.5X faster!
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Enumerable#reverse and Enumerable#each
versus Enumerable#reverse_each
enum.reverse.each do
# do something
end
enum.reverse_each do
# do something
end
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Results
slow 156173.2 (±9.2%) i/s
fast 182859.3 (±7.8%) i/s
17% faster!
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Hash#keys and Enumerable#each
versus Hash#each_key
hash.keys.each do |k|
# do something
end
hash.each_key do |k|
# do something
end
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Results
slow 34702.1 (±9.8%) i/s
fast 46103.3 (±8.1%) i/s
Over 33% faster!
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Array#shuffle and Array#first
versus Array#sample
array.shuffle.first array.sample
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Results
slow 324806.7 (±8.1%) i/s
fast 5069719.9 (±9.5%) i/s
Over 15X faster!
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Hash#merge versus Hash#merge!
enum.inject({}) do |h, e|
h.merge(e => e)
end
enum.inject({}) do |h, e|
h.merge!(e => e)
end
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Results
slow 33572.0 (±3.3%) i/s
fast 106473.0 (±3.4%) i/s
Over 3X faster!
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Hash#merge! versus Hash#[]=
enum.each_with_object({}) do |e, h|
h.merge!(e => e)
end
enum.each_with_object({}) do |e, h|
h[e] = e
end
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Results
slow 99331.3 (±2.2%) i/s
fast 217944.4 (±5.2%) i/s
Over 2X faster!
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Hash#fetch versus Hash#fetch with block
{:ruby => :conf}.fetch(:ruby, (0..9).to_a)
{:ruby => :conf}.fetch(:ruby) { (0..9).to_a }
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Results
slow 712384.2 (±3.8%) i/s
fast 1590417.4 (±4.1%) i/s
Over 2X faster!
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String#gsub versus String#sub
‘http://rubyconf.pt/'.gsub(‘http://', 'https://')
'http://rubyconf.pt/'.sub('http://', 'https://')
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Results
slow 404148.2 (±4.6%) i/s
fast 602661.1 (±3.4%) i/s
50% faster!
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String#gsub versus String#tr
'slug from title'.gsub(' ', '_')
'slug from title'.tr(' ', '_')
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Results
slow 311878.2 (±3.5%) i/s
fast 1573891.1 (±4.6%) i/s
Over 5X faster!
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Parallel versus sequential assignment
a, b = 1, 2 a = 1
b = 2
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Results
slow 5821588.3 (±6.0%) i/s
fast 8010420.3 (±5.5%) i/s
40% faster!
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Using exceptions for control flow
begin
ruby.conf
rescue NoMethodError
'conf'
end
if ruby.respond_to?(:conf)
ruby.conf
else
'conf'
end
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Results
slow 328886.4 (±5.0%) i/s
fast 3348327.9 (±9.0%) i/s
Over 10X faster!
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Using throw/catch for control flow
begin
ruby.conf
rescue NoMethodError
'conf'
end
catch(:ruby) do
if ruby.respond_to?(:conf)
ruby.conf
else
throw(:ruby, ‘conf’)
end
end
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Results
slow 252474.2 (±8.4%) i/s
fast 1411916.6 (±7.2%) i/s
Over 5X faster!
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The Future
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Special Thanks
Aaron Patterson
Ruby Rogues Parley
Sam Saffron
Aman Gupta
Don Knuth
Yukihiro Matsumoto
Koichi Sasada
RubyConf Portugal
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