gistfile1.rb

require 'benchmark'

class A
  attr_accessor :foo

  def initialize
    @foo = 0
  end

  def test_direct
    10_000_000.times do
      @foo += 1
    end
  end

  def test_indirect
    10_000_000.times do
      self.foo += 1
    end
  end
end

Benchmark.bmbm do |x|
  x.report { A.new.test_direct }
  x.report { A.new.test_indirect }
end

gistfile2.txt

~❯ ruby test.rb
Rehearsal ------------------------------------
   0.590000   0.000000   0.590000 (  0.596101)
   1.390000   0.000000   1.390000 (  1.385770)
--------------------------- total: 1.980000sec
   
       user     system      total        real
   0.590000   0.000000   0.590000 (  0.589786)
   1.390000   0.000000   1.390000 (  1.391612)

~❯ rbx test.rb
Rehearsal ------------------------------------
   0.913333   0.000000   0.913333 (  0.915784)
   0.796667   0.003334   0.800001 (  0.802277)
--------------------------- total: 1.713334sec
   
       user     system      total        real
   0.603334   0.000000   0.603334 (  0.607688)
   0.493333   0.000000   0.493333 (  0.496039)