ruby String#+ vs interpolation benchmark

string_bench.rb

require 'faker'
require 'benchmark'

times = 10000000
str = 'hello world'
Benchmark.bm do |b|
  b.report("+ with space") do
    times.times do
      str + str
    end
  end
  b.report("+ without space") do
    times.times do
      str + ' ' + str
    end
  end
  b.report("interpolation") do
    times.times do
      "#{str}#{str}"
    end
  end
end

       user     system      total        real
+ with space  3.110000   0.030000   3.140000 (  3.166537)
+ without space  9.210000   0.050000   9.260000 (  9.274476)
interpolation  3.490000   0.020000   3.510000 (  3.525237)