Queue with finite number of threads pattern

threads.rb

@threads = []
@num_of_threads = 8
@queue = Queue.new
# fill queue with items ...

@num_of_threads.times do
  @threads << Thread.new {
    loop do
      break if @queue.length == 0
      do_something @queue.deq
    end
  }
end
@threads.each { |thread| thread.join }