From: Justin Collins <justincollins@...>
Date: 2009-06-03T19:09:05+09:00
Subject: Re: gserver hogging CPU

Ezra Zygmuntowicz wrote:
>
> 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.

Indeed.

Much better to do:

  server.join

instead of using the loop.

-Justin