rubyのthread

Queue をpopするとき、空だと、Threadは、sleep(stop)するらしい。join中に、すべてのThreadが、sleep(stop)だと、dead lockとなるらしい。

indou@MacBook:work:$ cat ts2.rb

require 'thread'

array_size = ARGV[0].to_i

q = Queue.new

10.times {|i| q.push "no:#{i}"}

q.push nil

arrays = Array.new(array_size) do |i|

  Thread.new do

    while cnt = q.pop

      puts "Thread #{i}: no:#{cnt}"

    end

  end

end

arrays.each do |t|

  t.join

end

puts "finish!!"

indou@MacBook:work:$ ruby ts2.rb 1

Thread 0: job0

Thread 0: job1

Thread 0: job2

Thread 0: job3

Thread 0: job4

Thread 0: job5

Thread 0: job6

Thread 0: job7

Thread 0: job8

Thread 0: job9

finish!!

indou@MacBook:work:$ ruby ts2.rb 2

Thread 0: job0

Thread 0: job2

Thread 0: job3

Thread 0: job4

Thread 0: job5

Thread 0: job6

Thread 0: job7

Thread 0: job8

Thread 0: job9

Thread 1: job1

ts2.rb:17:in `join': deadlock detected (fatal)

     from ts2.rb:17:in `block in

'

     from ts2.rb:16:in `each'

     from ts2.rb:16:in `

'

indou@MacBook:work:$ diff ts2.rb ts2.2.rb

7c7,10

< q.push nil

---

> array_size.times do

>   puts "."

>   q.push nil

> end

indou@MacBook:work:$ ruby ts2.2.rb 1

.

Thread 0: job0

Thread 0: job1

Thread 0: job2

Thread 0: job3

Thread 0: job4

Thread 0: job5

Thread 0: job6

Thread 0: job7

Thread 0: job8

Thread 0: job9

finish!!

indou@MacBook:work:$ ruby ts2.2.rb 2

.

.

Thread 0: job0

Thread 0: job1

Thread 0: job2

Thread 0: job3

Thread 0: job4

Thread 0: job5

Thread 0: job6

Thread 0: job8

Thread 0: job9

Thread 1: job7

finish!!

indou@MacBook:work:$