bench_ivar_set.rb

require 'benchmark/ips'

# initialized
class A
  def initialize
    @c = @d = @e = @f = @g = @h = nil
  end
  def b
    @c || @d || @e || @f || @g || @h
  end
end

# not initialized
class B
  def initialize
    # nothing
  end
  def b
    @c || @d || @e || @f || @g || @h
  end
end

N = 10 # 1000
eval "def a0; #{"A.new;"*10} end"
eval "def b0; #{"B.new;"*10} end"

Benchmark.ips do |x|
  x.iterations = 2
  x.report('initialized') { a0 }
  x.report('uninitialized') { b0 }
  x.compare!
end