Hi, a couple of quick ways....clunky hacks for win32.

while(<$new_sock>) {
    my $input = chomp $_; 
    #print $_;  
    $canvas->update_graph( $input  )  # pseudocode to demo point :-)
    $mw->update;   # force the event loop to auto update the window
  }
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Ideally, you don't want to use a $mw->update in a while() loop. A timer is better, but may not be as fast.....although it will allow you to run other subs in the eventloop simultaneously with the socket connection.... like watching for a value to trip an alarm.

my $timer = $mw->repeat(10, \&update_graph);
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thats better. Then in the update_graph sub, read your socket, and update the canvas. You can start a second timer to watch for values, as they come in( store the last 10 values in a buffer)). It's all an event-loop system underneath......very powerful and useful once you get the idea. :-) Gtk2's event-loop is even more powerful than Tk's.