From: Robert Klemme <shortcutter@...>
Date: 2006-05-10T16:05:26+09:00
Subject: Re: garbage-collection question OR ruby-gnome bug?

2006/5/10, Cam <cameron.matheson@gmail.com>:
> Hi,
>
> My friend and I have been writing an application that makes extensive
> use of gdkpixbuf's, but they never get de-allocated.  I'm not entirely
> sure how the garbage-collector works internally in ruby, but my
> program quickly grows to over 114M pretty routinely.  My friend wrote
> a simple demonstration script:
>
> require 'gtk2'
> Gtk.init
> path = ARGV.pop
> raise "Pass a large image on the command line" unless path
> puts "Look at how much memory I'm using, then press enter"
> gets #1
> buf = Gdk::Pixbuf.new( path )
> puts "Now I've allocated the pixbuf, I should be using more memory."
> puts "Hit enter to dereference the pixbuf."
> gets #2
> buf = nil
> puts "Done.  Press enter to exit."
> gets #3
>
> Ok, here's the memory usage between various stages:
>
> 1:
> 1000     17271  0.3  2.4  15744  9312 pts/5    S+   23:03   0:00 ruby pixbuf.rb
>
> 2:
> 1000     17271  0.3  4.1  22448 16228 pts/5    S+   23:03   0:00 ruby pixbuf.rb
>
> 3:
> 1000     17271  0.3  4.1  22448 16228 pts/5    S+   23:03   0:00 ruby pixbuf.rb
>
> Now this example is much more trivial than the program we're trying to
> right, but they're both having this issue w/ the pixbuf's never being
> de-allocated.  Is this a known bug?  Is there something we can do to
> force the GC to take care of them?

I can only say something about your short demo piece because I don't
have the other code. It's quite unlikely that you see the GC kick in
before program termination here.  GC kicks in when the interpreter
decides to do it - not necessarily soon after an object has become
unreachable.  This is really only a problem if you have a long running
version and it keeps using more memory over time.  I suggest you
modify your script by removing lines with "gets" and put the whole
thing in a loop say 10,000 times.  Then watch how memory usage
develops.  If it's linearly increasing your chances are that there is
a bug in Gdk or you're using it the wrong way (i.e. do not release Gdk
resources as required by the lib).

HTH

robert

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