Re: [matplotlib-devel] memory leaks

[Eric F. <ef...@ha...>]

Tom Holroyd (NIH/NIMH) [E] wrote:
> More info on the memory leaks. It has to do with GtkToolbar.insert(). 
> For example, in the function _init_toolbar2_4() in backend_gtk.py, 
> commenting out any of the self.insert() calls will change how much it 
> leaks. Comment them all out, plus the self.fileselect assignment (which 
> is very slow, by the way, and accounts for more leaks than other places) 
> and it'll leak minimally.
> 
> Does that mean this is a bug in gtk?
> 

I don't know.  I have been experimenting with a simple pure pygtk demo 
(no mpl components).  I was about to conclude that it leaked whenever 
the toplevel show() method was used, but I just now did another test 
that suggests this is not the case if the mainloop in started and the 
window is killed each time--which would be the normal mode of operation, 
but is tedious to test for large numbers of iterations. (It should be 
possible to simulate it instead.) I have not tried enough of such loops 
to be sure yet, but overall, I am suspecting that the problem in mpl is 
not inevitable but has to do with the way the gtk things are called and 
referenced.  I think we have a similar problem with all interactive 
backends (the only one I didn't test is Qt4Agg) which also makes me 
suspect we are violating some gui rule, rather than that gtk, qt3, wx, 
and tk all have leaks.

I added a MemoryMonitor class to cbook.py to make this testing a little 
easier.  No docstrings yet, but it will be obvious what it does.

Eric