From: "Iñaki Baz Castillo" <ibc@...>
Date: 2008-03-27T19:47:23+09:00
Subject: Re: "loop do IO.select([io], nil, nil)" eats 95% of CPU, any other way?

2008/3/27, Iñaki Baz Castillo <ibc@aliax.net>:

>  But now I try a similar way using GServer (that implements a TCP
>  multithreaded server):
>
>  ----------- io2.rb ----------------
>  #!/usr/bin/env ruby
>
>  require 'gserver'
>
>
>  class Server < GServer
>
>         def initialize(port=2000)
>                 super(port)
>         end
>
>         def serve(io)
>
>                 puts "------------ serve(io) -------------"
>                 loop do
>                         p "-- second loop --"
>
>                         ready, = select([io], nil, nil, nil).first
>                         break if ready.nil?
>                         p ready.read(10)
>
>                         break if ready.eof?
>                 end
>
>                 puts "---------- end server(io) ------------"
>         end
>
>  end
>
>  server = Server.new
>  server.audit=true
>  server.start
>
>  loop do
>         #puts "----- main loop -----"
>         break if server.stopped?
>  end
>  -------------------------------------
>
>
>  ~# ./io2.rb
>  ----- main loop -----
>  ----- main loop -----
>  ----- main loop -----
>  ----- main loop -----
>  ...
>
>  So there is no connection yet but Ruby is doing a loop and eating 90%
>  of CPU. Why??


>  I will try to do the same without GServer or threads, using TCPServer
>  class and so.

I've tryed now with TCPServer alone (and Threads) without GServer and
this loop issue doesn't occur:

--- io3.rb ------------------------------------
#!/usr/bin/env ruby

require 'socket'

server = TCPServer.open(2000)

loop do
  p "------- main loop --------"
  socket = server.accept

  Thread.start do # one thread per client

       s = socket
        loop do
                select([s], nil, nil, nil)
                break if s.nil?
                p s.read(10)
                break if s.eof?
        end

   end

end
------------------------------------------------------


~# ./io3.rb
"------ main loop ------"  (and waits)

~# echo "1234567890" | nc 127.0.0.1 2000
"------ main loop ------"
"1234567890"


So I don't know why but using GServer the main loop runs all the time
while witout using GServer it doesn't occur ¿?