From: Ezra Zygmuntowicz <ezmobius@...>
Date: 2009-06-03T14:26:06+09:00
Subject: Re: gserver hogging CPU


On Jun 2, 2009, at 7:25 PM, Scott Cole wrote:

> I'm running a server on Mac OS 10.5.7, Ruby 1.8.6, that's almost  
> exactly
> the same as the one in Peter Cooper's Beginning Ruby book. When I run
> the Activity Monitor it shows Ruby is consuming about 98% of one of my
> CPUs when there's no client activity (I have only 3 clients, 2 in the
> same computer). I need the computer for other important things, so  
> this
> concerns me.
>
> What can I do to free up the CPU? I've tried adding a few sleeps, to  
> not
> avail. Here's the code:
> -------------------------------
> #!/usr/bin/env ruby
>
> # Start this server with
> # ruby -w GServerchat.rb <port#>
> # or just
> # GServerchat.rb <port#>    if file is executable
> #
>
> require 'gserver'
>
> class ChatServer < GServer  # Server class derived from GServer super
> class
>  def initialize(*args)
>    super(*args)
>
>    # Keep a record of the client IDs allocated
>    # and the lines of chat
>    @@client_id = 0
>    @@chat = []
>  end
>
>  def serve(io)             # Serve method handles connections
>  # Increment the client ID so each client gets a unigue ID
>      @@client_id += 1
>      my_client_id = @@client_id
>      my_position = @@chat.size
>
>      io.puts("welcome, client #{@@client_id}!")
>
>      #leave a 'joined' message on the chat queue
>      @@chat << [my_client_id, "<joins the chat>"]
>
>      loop do
>      #Every 2 seconds check for data
>      if IO.select([io], nil, nil, 2)
>      # If so, retrieve the data and process it...
>      line = io.gets
>
>      # Write the new line to the log file
>    logfile = File.open('/tmp/chatlog', 'a')
>    logfile.puts line
>    logfile.close
>
>      # If user says quit, disconnect them
>      if line =~ /quit/
>        @@chat << [my_client_id, "< leaves the chat>"]
>        break
>      end
>
>      # Shut down the server if we hear 'shutdown'
>      self.stop if line =~ /shutdown/
>
>      # Add the client's text to the chat array along with client's ID
>
>      @@chat << [my_client_id, line]
>    else
>      # No data, so print any newlines from the chat stream
>      @@chat[my_position..(@@chat.size - 1)].each_with_index do |line,
> index|
>        io.puts("#{line[0]} says: #{line[1]}")
>       end
>
>       #Move the position to one past array end
>      my_position = @@chat.size
>      end
>   end
>
>
>  end
> end
>
> ##server = ChatServer.new(ARGV[0])
>
> portnum = ARGV[0] || 50000
> my_ip =
> Socket::getaddrinfo(Socket.gethostname,"echo",Socket::AF_INET)[0][3]
> server = ChatServer.new(portnum, my_ip, 5, $stdout, true)
>
> server.start              # Start the server
>
> loop do
>  break if server.stopped?
> end

	This last loop looks suspect. You are basically calling  
server.stopped? in a loop as fast as you can. Try sleeping a bit in  
that loop:

loop do
   sleep 1
   break if server.stopped?
end

Cheers-
Ezra Zygmuntowicz
ez@engineyard.com