From: ahoward <ahoward@...>
Date: 2003-02-27T00:15:37+09:00
Subject: Re: Ruby in Performance Testing

On Wed, 26 Feb 2003, E F van de Laar wrote:

<snip>
> I also get "Bad file descriptor" errors at times.
<snip>

> #!/usr/bin/ruby -w
>
> require 'socket'
> require 'thread'
>
> threads = []
>
> (1..500).each do |c|
>   threads << Thread.new(c) do |client|
>     (1..10).each do |request|
>       begin
>         TCPSocket::open('localhost', 80) { |s|
>           # perform some socket reading writing here
>           # and print some output
                  ^^^^^^^^^^^^^^^^^
>         }
>       rescue Exception => e
>         $stderr.puts e
          ^^^^^^^^^^^^^^
>       end
>     end
>   end
> end
>
> threads.each { |t|
>   t.join
> }

i'm not sure, but accessing stdout/stderr from this many threads at once may
be a problem - i've had problems with it before.  one thing i've done in my
threaded problems is something like this :

  #!/usr/bin/env ruby
  require 'thread'

  tds = []
  toutput = []
  sem = Mutex.new

  4.times do |tid|
    toutput[tid] = []
    tds <<
      Thread.new (tid) do
	2.times do |i|
	  Thread.pass while not sem.try_lock
	    toutput[tid] << "msg #{i} from thread #{tid}..."
	  sem.unlock
	end
      end
  end

  toutput.each do |msgs|
    msgs.each do |msg|
      puts msg
    end
    puts
  end


which would output :

  msg 0 from thread 0...
  msg 1 from thread 0...

  msg 0 from thread 1...
  msg 1 from thread 1...

  msg 0 from thread 2...
  msg 1 from thread 2...

  msg 0 from thread 3...
  msg 1 from thread 3...


this technique alone has helped my concurrent programming skiils since i can
read the bloody output!


-a







>
> Emiel
> --
> E F van de Laar
> +31648183479
> www.il.fontys.nl/~emiel
>
>

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