Ruby string operation benchmark

ree 1.8.7 result

rainux@immortal ~/devel/twi_meido
% YUKI.N> ruby d.rb
      user     system      total        real
  0.770000   0.020000   0.790000 (  0.802016)
  0.730000   0.000000   0.730000 (  0.740943)
  0.760000   0.020000   0.780000 (  0.793928)
      user     system      total        real
  1.160000   0.010000   1.170000 (  1.182798)
  1.230000   0.030000   1.260000 (  1.268377)

ruby 1.9.2 result

rainux@immortal ~/devel/twi_meido
% YUKI.N> ruby d.rb
      user     system      total        real
  0.880000   0.000000   0.880000 (  0.895912)
  0.740000   0.010000   0.750000 (  0.756707)
  0.890000   0.020000   0.910000 (  0.926466)
      user     system      total        real
  1.560000   0.010000   1.570000 (  1.582597)
  1.840000   0.000000   1.840000 (  1.837688)

ruby_str_bm.rb

# encoding: UTF-8
require 'benchmark'

n = 500000

Benchmark.bm do |x|
  x.report do
    n.times do
      str = 'Ruby string operation benchmark'
      str << 'a random string'
    end
  end

  x.report do
    n.times do
      str = 'Ruby string operation benchmark'
      str = str + 'a random string'
    end
  end

  x.report do
    n.times do
      str = 'Ruby string operation benchmark'
      str = "#{str}a random string"
    end
  end
end

a = 'AAAAAAA'
b = 'BBBBBBBBBBB'
c = 'CCCCCCCCCCCCCCCCCCCCCCCCC'

Benchmark.bm do |x|
  x.report do
    n.times do
      str = "#{a} some string #{b} some string #{c}"
    end
  end

  x.report do
    n.times do
      str = "%s some string %s some string %s" % [a, b, c]
    end
  end
end