[maemo-developers] python2.5 - unnecessary multiple processes forked

[From: Alex Iliadis]

I recommend using the garbage collector module manually to override the 
defaults. Python for some reason doesn't reclaim memory fast. So if you 
put in your code:
import gc
gc.collect()  (at the right spots, probably after the file chooser dialog 
and after some memory intensive tasks). You should notice a lot of memory 
being free'd up.

-Alex

On Sunday 30 December 2007 05:20:34 pm Jayesh Salvi wrote:
> Hi,
>
> I am porting a pygtk application to maemo. It works alright, but I
> noticed that it was consuming lot of memory, preventing me from opening
> other applications.
>
> When I investigated, I found that my python application was forking 4
> more instances of itself, each one identical in memory footprint. Thus
> they consumed nearly 60-70% of my memory.
>
> So I ran my application using pdb and narrowed down to a code segment
> that was leading to multiple instances of the process. It turned out
> that when I call run() on hildon.fileChooserDialog object, the dialog
> opens and at that moment in the "top" I see 4 more instances being
> forked.
>
> I fail to understand this behavior. I replaced the hildon widgets by
> pure gtk widgets and I see similar behavior, except that 2 more
> instances get forked. Also when using gtk.FileChooserDialog, these new
> instances get created in the instantiation of the dialog object, rather
> than call to run(). (code included below)
>
> So to further explore the problem, I ran same application on my desktop
> with gtk widgets. But I verified that when fileChooserDialog's run is
> called, there are no additional instances of python.
>
> I am running this code on n770, with 2007 HE and python2.5 runtime. My
> application code is pure python and not using any additional libraries.
> In fact following would be a simpler version of it to reproduce the
> problem:
>
> import gtk
> import hildon
>
> #window = gtk.Window(gtk.WINDOW_TOPLEVEL)
>
> #fileChooser = gtk.FileChooserDialog(
> #       title="Choose a photo to publish",
> #       buttons=(gtk.STOCK_CANCEL, gtk.RESPONSE_CANCEL,
> #       gtk.STOCK_OK, gtk.RESPONSE_OK))
>
> fileChooser = hildon.FileChooserDialog(
>         window,gtk.FILE_CHOOSER_ACTION_OPEN)
>
>
> result = fileChooser.run()
>
> if result == gtk.RESPONSE_OK:
>         print fileChooser.get_filename()
>
> Do you have any tips, as to what might be going wrong?
>
> This problem is fatal at least on n770 - it will trigger low memory
> message when other applications are used on the side.
>
> Any help will be useful.
>
> Thanks,