Re: gtkperf regression and gtknotebook

["Padraig O'Briain" <Padraig Obriain Sun COM>]

Matthias Clasen wrote:
> On 7/5/06, Padraig O'Briain <Padraig Obriain sun com> wrote:
>   
> > Our QA team has reported roughly a 10% degradation in gtkperf
> > performance when comparing GNOME 2.6 and GNOME 2.14.
> >
> > GNOME 2.6 is using gtk 2.4.9 and GNOME 2.14 is using gtk 2.8.17.
> >
> > gtkperf is CPU bound and most of the CPU is used by the X server.I used
> > a special version of Xorg with dtrace probes, see
> > http://people/freedesktop.org/~alanc/dtrace, to identify that most of
> > the CPU is being used by the RENDER extension and within that by
> > RenderComposite
> > requests.
> >
> > The worst degradation is being seen in the first three tests in gtkperf,
> > i.e. GtkEntry, GtkComboBox and GtkComboBoxEntry.
> >
> > Most of the RenderComposite requests are inexpensive but there are a
> > handful of expensive ones. In one example I am looking at 18 calls out
> > of 444 each take about the same amount of time and account for roughly
> > 2/3 of the total cost.
> >
> > All the expensive XRenderComposite calls seem to be associated with
> > calls to gtk_paint_box_gap which is called from gtk_notebook_paint which
> > is called from gtk_notebook_expose.
> >
> > I have looked at all the calls to gtk_paint_box_gap during one iteration
> > of GtkEntry, GtkComboBox and GtkComboBoxEntry tests in gtkperf using gtk
> > 2.4 and gtk 2.8 to see if there is any correlation between the arguments
> > passed to gtk_paint_box_gap and the expensive calls. It looks like the
> > expensive calls are the ones with the largest area. See data below.
> >
> > I am looking for help at this stage.
> >
> > Should we expect the calls to gtk_paint_box_gap to be so expensive?
> >     
>
> What part of it is expensive ?
>
> I am a bit puzzled, since it seems to
> be only a) clear the background and b) draw a bunch of lines.
> a) should now use core X protocol, not render/cairo (see
> setup_backing_rect_method)
> b) should also just use core X protocol
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>   
I meant the cost in the Xserver of the XRenderComposite calls made by 
functions called by gtk_paint_box_gap rather than gtk_paint_box_gap itself.

I am not sure that cairo has anything to do with it; XRenderComposite is 
being called from draw_with_pixmaps in gdk/x11/gdkdrawable-x11.c.

Since I sent the original mail, I have noticed,when using gtk 2.8, a 
call to gtk_paint_flat_box
with what looks like an abnormally large value for width. I need to 
follup up that lead.

Padraig