Multi-threading example in ruby.

multi_thread_ruby.rb

num_iterations = 20
num_threads = 4

# Try counting to 1 million on 4 separate threads 20 times
total_time = 0.0
num_iterations.times do |iter|
  threads = []
  t_0 = Time.now
  for i in 1..num_threads
    threads << Thread.new(i) { |t|
      count = 0
      1000000.times do
        count += 1
      end
    }
  end

  # Wait for all threads to complete
  threads.each { |thread| thread.join }
  t_1 = Time.now

  time_ms = (t_1-t_0) * 1000
  puts "TEST #{iter}: Time elapsed = #{time_ms}ms"
  total_time +=  time_ms
end

puts "Average completion time: #{total_time/num_iterations}"