gistfile1

require 'open-uri'
require 'benchmark'

urls = []
urls << "http://ruby-lang.org"
urls << "http://theplatform.com"
urls << "http://reddit.com"
urls << "http://pragprog.com"
urls << "http://railscasts.com"

def threaded(urls)
  thread_list = []
  urls.each do |f|
    thread_list  << Thread.new {
      open(f) do |x|
         x.read
      end
      puts "reading: " + f
    }
  end
  thread_list.each {|x| x.join}
end

def sequential(urls)
  urls.each do |f|
    open(f) do |x|
      x.read
    end
    puts "reading: " + f
  end
end

Benchmark.bm do |x|
  x.report("Threaded:\n")   { threaded(urls) }
  x.report("Sequential:\n") { sequential(urls) }
end

   user     system      total        real

Threaded:
reading: http://pragprog.com
reading: http://reddit.com
reading: http://railscasts.com
reading: http://theplatform.com
reading: http://ruby-lang.org
0.060000 0.030000 0.090000 ( 2.438356)
Sequential:
reading: http://ruby-lang.org
reading: http://theplatform.com
reading: http://reddit.com
reading: http://pragprog.com
reading: http://railscasts.com
0.040000 0.010000 0.050000 ( 4.286305)