More results:

I've built and tested a more recent pygtk+ stack.  (glib-2.12, 
gtk+-2.10.9, librsvg-2.16.1, libxml2-2.6.29, pygobject-2.13.1, 
pygtk-2.10.4...).  The good news is that the C-level leaks I was seeing 
in pygtk 2.2 and 2.4 are resolved.  In particular, using an SVG icon and 
Gdk rendering no longer seems problematic.  I would suggest that anyone 
using old versions of pygtk should upgrade, rather than spending time on 
workarounds for matplotlib -- do you all agree?  And my Gtk patch should 
probably be reverted to use an SVG icon for the window again (or to only 
do it on versions of pygtk > 2.xx).  I don't know what percentage of 
users are still using pygtk-2.4 and earlier...

There is, however, a new patch (attached) to fix a leak of 
FileChooserDialog objects that I didn't see in earlier pygtk versions.  
I have to admit that I'm a bit puzzled by the solution -- it seems that 
the FileChooserDialog object refuses to destruct whenever any custom 
Python attributes have been added to the object.  It doesn't really need 
them in this case so it's an easy fix, but I'm not sure why that was 
broken -- other classes do this and don't have problems (e.g. 
NavigationToolbar2GTK).  Maybe a pygtk expert out there knows what this 
is about.  It would be great if this resolved the linear memory growth 
that Eric is seeing with the Gtk backend.

GtkCairo seems to be free of leaks.

QtAgg (qt-3.3) was leaking because of a cyclical reference in the 
signals between the toolbar and its buttons.  (Patch attached).

Qt4 is forthcoming (I'm still trying to compile something that runs the 
demos cleanly). 

I tried the FltkAgg backend, but it doesn't seem to close the window at 
all when the figure is closed -- instead I get dozens of windows open at 
once.  Is that a known bug or correct behavior?

Cheers,
Mike

Eric Firing wrote:
> Michael Droettboom wrote:
>> Eric Firing wrote:
>>> So, this test is still showing problems, with similar memory 
>>> consumption in these three backends.
>> Not necessarily.  By default, Python allocates large pools from the 
>> operating system and then manages those pools itself (though its 
>> PyMalloc call).  Prior to Python 2.5, those pools were never freed.  
>> With Python 2.5, empty pools, when they occur, are freed back to the 
>> OS.  Due to fragmentation issues, even if there is enough free space 
>> in those pools for new objects, new pools may need to be created 
>> anyway, since Python objects can't be moved once they are created.  
>> So seeing modest increases in memory usage during a long-running 
>> Python application is typical, and not something that can be avoided 
>> wiinaccurate at finding memory leaksthout micro-optimizing for pool 
>> performance (something that may be very difficult).  If memory usage 
>> is truly increasing in an unbounded way, then, yes, there may be 
>> problems, but it should eventually stabilize (though in a test such 
>> as memleak_gui that may take many iterations).  It's more interesting 
>> to see the curve of memory usage over time than the average over a 
>> number of iterations.
>
> I agree.  I just ran 2000 iterations with GtkAgg, plotted every 10th 
> point, and the increase is linear (apart from a little bumpiness) over 
> the entire range (not just the last 1000 iterations reported below):
>
> Backend GTKAgg, toolbar toolbar2
> Averaging over loops 1000 to 2000
> Memory went from 31248k to 35040k
> Average memory consumed per loop: 3.7920k bytes
>
> Maybe this is just the behavior of pymalloc in 2.5?
>
>
>> For further reading, see:
>> http://evanjones.ca/python-memory.html
>> README.valgrind in the Python source
>> http://mail.python.org/pipermail/python-dev/2006-March/061991.html
>>
>> Because of this, using the total memory allocated by the Python 
>> process to track memory leaks is pretty blunt tool.  More important 
>> metrics are the total number of GC objects (gc.get_objects()), GC 
>> garbage (gc.garbage), and using a tool like Valgrind or Purify to 
>> find mismatched malloc/frees.  Another useful tool (but I didn't 
>> resort to yet with matplotlib testing) is to build Python with 
>> COUNT_ALLOCS, which then gives access to the total number of mallocs 
>> and frees in the Python interpreter at runtime.
>>
>> IMO, the only reasonable way to use the total memory usage of Python 
>> to debug memory leaks is if you build Python without pool allocation 
>> (--without-pymalloc).  That was how I was debugging memory leaks last 
>> week (in conjunction with valgrind, and the gc module), and with that 
>> configuration, I was only seeing memory leakage with Pygtk 2.4, and a 
>> very small amount with Tk.  Are your numbers from a default build?  
>> If so, I'll rebuild my Python and check my numbers against yours.  If 
>> they match, I suspect there's little we can do.
>
> I used stock Python 2.5 from ubuntu Feisty.  I should compile a 
> version as you suggest, but I haven't done it yet.
>
> Eric
>
>>
>> Cheers,
>> Mike
>>
>
>


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