Benchmark for Class method vs. instance method

class_vs_instance_method.rb

# The verdict: Doesn't matter which one.


class MethodTesterObject
  class << self
    def perform(instances)
      instances.each { |obj| obj.action }
    end
  end
  
  attr_accessor :value
  def initialize
    self.value = rand(36**8).to_s(36)
  end
  
  def perform
    self.action
  end
  
  def action
    1000.times { self.value * 100 }
  end
end

class MethodTester
  def self.run
    instances = []
    1000.times { instances.push MethodTesterObject.new }
    
    puts "Running instance method."
    puts Benchmark.measure { instances.each { |i| i.perform } }
    
    puts "Running class method."
    puts Benchmark.measure { MethodTesterObject.perform(instances) }
  end
end

results

1.9.3p0 :099 > MethodTester.run
Running instance method.
  1.210000   0.180000   1.390000 (  1.385852)
Running class method.
  1.200000   0.160000   1.360000 (  1.358509)
 => nil 
1.9.3p0 :100 > MethodTester.run
Running instance method.
  1.150000   0.140000   1.290000 (  1.287323)
Running class method.
  1.140000   0.140000   1.280000 (  1.282318)
 => nil 
1.9.3p0 :101 > MethodTester.run
Running instance method.
  1.150000   0.140000   1.290000 (  1.287659)
Running class method.
  1.170000   0.150000   1.320000 (  1.316425)
 => nil