[Eric] understanding eric4 slowness

[Detlev Offenbach]

On Freitag, 13. April 2007, Phil Thompson wrote:
> On Friday 13 April 2007 7:01 pm, Detlev Offenbach wrote:
> > On Freitag, 13. April 2007, Andreas Pakulat wrote:
> > > On 13.04.07 19:26:28, Detlev Offenbach wrote:
> > > > On Mittwoch, 11. April 2007, Andreas Pakulat wrote:
> > > > > c) How do I do performance tests on eric4? I tried the profile
> > > > > project option in eric3 but after the splash screen vanishes
> > > > > nothing seems to happen.
> > > >
> > > > Over here it took some time to show up on the first run.
> > >
> > > I'll try that again some time.
> > >
> > > > > All in all eric3 seems to be much faster than eric4.
> > > >
> > > > That is what I observed as well. However, I was not able to find the
> > > > real cause. All in all I have the impression, that Qt4 is slower than
> > > > Qt3. I have observed this with other (pure) Qt applications as well
> > > > (both at work and at home, both on Linux and on win32). I got the
> > > > impression, that the problem is worse on Linux.
> > >
> > > Hmm, I don't think I have a Qt4 app with a larger model, however I do
> > > have experience with KDE4 and at least their filesystem-model is pretty
> > > fast. So I'm not so 100% sure its just the Qt4 model/view stuff, it may
> > > still be related to how the models are implemented. Anyway, I'll try to
> > > get some profiling data and see what it can tell me...
> > >
> > > Andreas
> >
> > It might not really be the model/view stuff. I have the impression it is
> > painting the data to the screen. If you load a really huge file in
> > QScintilla2 (e.g. ViewManager.py or UserInterface.py) and enter some text
> > at the beginning of the file, you shouldn't type too fast or you'll lose
> > some keystrokes. This is just an example. I have seen slow paintings in
> > various areas. As I said, this was observed in other Qt4 applications as
> > well.
>
> It could be painting or it could be font handling. Scintilla renders the
> whole of a document when word wrap is enabled - so it knows how many lines
> there are. I don't think you should notice problems if word wrap is
> disabled.
>

Ok, it seems in case of QScintilla it is word wrap, that causes the slow down. 
I just disabled it and it was a few factors faster.

Detlev
-- 
Detlev Offenbach
detlev at die-offenbachs.de