From: Bob Calco <rcalco@...>
Date: 2001-12-26T23:03:14+09:00
Subject: [ruby-talk:29440] Tk / IO question

I'm experiencing some rather significant performance problems with IO.popen
when embedding the logic in a Tk app. I'm using Drb to remotely execute
processes and redirect their output to a monitor. Run as a console its (to
my naked eye), it's blazing fast, even when the controller/server/monitor
are on different machines on the network. However, when run in a Tk GUI --
where the only difference is that Tk.mainloop is keeping the service running
vs. DRbObject.thread.join (when run as a console), the slowdown is palpable,
I suppose because of the Tk event loop.

I didn't benchmark it, but the following

IO.popen("#{cmd}","r+") { |ruby|
  @@jobs += 1
  job = @@jobs
  while ruby.gets
    monitor.write($_)
  end
  ruby.close_write
}

...goes from pumping stuff almost instantaneously to the monitor, even if
its on a separate machine, to running something like this even when
everything is on the same machine , assuming the command is "ruby -e \"for i
in 1..10 do;puts i.to_s;end\"" (forgive the crude visualization, which is
inaccurate in that it does not illustrate the newline after each output):

1 . . . 2 . . . 3. . . 4. . . 5 . . .6 . . .7. . .8 . . . 9. . . 10

(whereas before it was 12345678910, speedwise).

Each tick is about a half a second, though it feels like an eternity.

I've tried blocking that whole process into a separate thread and everything
but it really seems like the execution of the while loop is what's holding
it up. Is there a way to turn the Tk.mainloop off for the duration of the
while loop? I'm more of a windows geek but have been trying to learn tk to
put together an IDLE-like GUI for a cross-platform control panel solution
that controls other machines and apps remotely. Maybe the answer is to run
the service as a console and that's it, but I'd like to put a gui on it.
Chances are though that my ignorance of Tk is the problem.

Sincerely,
____         _       ___        _
|   \       | |     /   )      | |
|___/   __  |/_    |      __,  | |  __   __
|   \  /  \_|  \_  |     /  |  |/  /  ) /  \_
|___/_/\__/ |__/    \___/\_/|_/|__/\___/\__/

Bob Calco
Centreville, Virginia

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Stupidity got us into this mess -- why can't it get us out?"
                       [Will Rogers]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~