gistfile1.rb

# 9 out of 10 microbenchmarks agree: implicit return smokes explicit return
require 'benchmark'

def with_explicit
  return 1
end

def with_implicit
  1
end

# rails returning
def returning(value)
  yield
  value
end

def with_returning
  returning(1) do
  end
end

n = 10_000_000

Benchmark.bmbm do |x|
  x.report("explicit") { n.times { with_explicit } }
  x.report("implicit") { n.times { with_implicit } }
  x.report("returning"){ n.times { with_returning } }
end

gistfile2.txt

# ruby 1.8.7 (2008-08-11 patchlevel 72) [i486-linux]
$ ruby test.rb 
Rehearsal ---------------------------------------------
explicit    8.190000   4.340000  12.530000 ( 12.705659)
implicit    6.550000   2.430000   8.980000 (  8.997430)
returning  14.930000   4.820000  19.750000 ( 19.910411)
----------------------------------- total: 41.260000sec

                user     system      total        real
explicit    8.410000   4.110000  12.520000 ( 12.826650)
implicit    7.020000   2.320000   9.340000 (  9.499807)
returning  15.410000   4.550000  19.960000 ( 20.093049)