Re: (severe) performance issues

["David J. Andruczyk" <djandruczyk yahoo com>]

And the GTK+ developers haven't fixed this because of what?  pride?

I've seen this issue in GTK+ for YEARS, and filed bug reports on it
for several years only to be shot down and turned away by them. 
That's disappointing.


--- Paul Davis <paul linuxaudiosystems com> wrote:

> On Mon, 2007-03-26 at 17:17 -0700, David J. Andruczyk wrote:
> > I hadn't tried that as I assumed that it was off by default
> unless
> > enabled..
> > 
> > Since a simple test program doesn't show it,.  but my app does
> and
> > the performance hogging goes away when I comment out one line
> > (gtk_label_set_text) the problem appears to be internal to GTK>
> 
> > Another fine fellow suggested it may be due to resizing of
> widgets
> > caused by the label update, and showed me a way to set it to a
> > fixed size,  but that ahd no effect on cpu usage (still high).
> > 
> > I managed to create a workaround by useing a GtkEntry instead,
> and
> > working out some trickery to make the entrie's background color
> > (normally white) to match it's parent so it blends in and looks
> > like a label, and presto, cpu usage went from 40-45% down to 4
> %.
> > 
> > For some reason in my case the label  updates seem to be
> triggering
> > some internal stuff for no good reason. when I get a little
> time
> > I'll try to extract that section of code int oan isolated test
> > case, and if it still shows that I'll file it as a GTK+ bug.
> 
> this is a sort of known "bug". setting the text of a label causes
> a
> recompute of the label's size, which can propagate up the
> containing
> widget tree. add Pango into the mix, and that resetting is very
> costly. 
> the same is not true of text entries, because they never resize
> based on
> their contents.
> 
> evolution, sodipodi (the precursor to inkscape) and a few other
> projects
> have implimented their own labels that do not do this, for
> precisely the
> reason you are now discovering.
> 
> (i would have replied sooner, but was away in berlin at the linux
> audio
> conference with no email access or time)
> 
> --p
> 
> 
> 
> 


-- David J. Andruczyk


 
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