cpu_bound.rb

require 'benchmark'

@threads = []
Benchmark.bm(14) do |x|
  x.report('no-threads') do
    8.times do
      tmp_array = []
      10_000_000.times { |n| tmp_array << n }
    end
  end

  x.report('with-threads') do
    8.times do
      @threads << Thread.new do
        tmp_array = []
        10_000_000.times { |n| tmp_array << n }
      end
    end
    @threads.each(&:join)
  end
end