Class vs struct vs hash vs openstruct instantiation performance

instantiation.rb

require 'benchmark'
require 'ostruct'

REP = 1000000

User = Struct.new(:name, :age)

class Obj
  def initialize(name, age)
    @name = name
    @age = age
  end
end


USER = "User".freeze
AGE = 21
HASH = {:name => USER, :age => AGE}.freeze

Benchmark.bm 20 do |x|

  x.report 'Class slow' do
    REP.times do |index|
       Obj.new("User", 21)
    end
  end


  x.report 'Class fast' do
    REP.times do |index|
       Obj.new(USER, AGE)
    end
  end


  x.report 'OpenStruct slow' do
    REP.times do |index|
       OpenStruct.new(:name => "User", :age => 21)
    end
  end



  x.report 'OpenStruct fast' do
    REP.times do |index|
       OpenStruct.new(HASH)
    end
  end

  x.report 'Struct slow' do
    REP.times do |index|
       User.new("User", 21)
    end
  end

  x.report 'Struct fast' do
    REP.times do |index|
       User.new(USER, AGE)
    end
  end

  x.report 'Hash slow' do
    REP.times do |index|
      {:name => 'User', :age => 21}
    end
  end

  x.report 'Hash fast' do
    REP.times do |index|
      {:name => USER, :age => AGE}
    end
  end
end

Results:

                           user     system      total        real
Class slow             0.310000   0.000000   0.310000 (  0.317348)
Class fast             0.230000   0.000000   0.230000 (  0.233508)
OpenStruct slow       11.740000   0.290000  12.030000 ( 13.258977)
OpenStruct fast       10.780000   0.240000  11.020000 ( 12.225826)
Struct slow            0.290000   0.000000   0.290000 (  0.296622)
Struct fast            0.220000   0.000000   0.220000 (  0.219298)
Hash slow              0.610000   0.030000   0.640000 (  0.717739)
Hash fast              0.530000   0.030000   0.560000 (  0.609345)