[Interest] Qt 5.0.2 speed and widgets

[Philippe]

I think I have found the problem: the qaccessible interface...

While my program was kind of hanging during those long seconds, I have
broken several times in the debugger, and saw that some accessibility
code was being executed. Then I did this quick Qt change:
in qaccessible.cpp
QAccessible::queryAccessibleInterface(...)
I insert "return 0;" at the start...
et voilà, back to normal speed! (actually, a 20% reduction compared to
4.8, but this is the day and night compared to before).
This code change is a dirty hack of course, but it simply make Qt 5 usable
again for me...

There is definitly something wrong on the Windows accessibility code...

Philippe

On Mon, 15 Apr 2013 07:45:55 +0200
"Michael Klank" <michael.klank at amk-antriebe.de> wrote:

> We have a similar problem here. I did compare a small (bigxml) program from
> http://qt-project.org/ which reads an xml file in a QTreeWidget and expands all
> nodes. The test xml file is 2MB. Qt5.0.2 MSVC2012 64Bit/32Bit is up to 20x
> slower than Qt4.8.0 MSVC2010 32Bit, in release mode!!! That's strange. And I
> didn't say anything from debug mode!
> 
> 
> -----Ursprüngliche Nachricht-----
> Von: interest-bounces+michael.klank=amk-antriebe.de at qt-project.org
> [mailto:interest-bounces+michael.klank=amk-antriebe.de at qt-project.org] Im
> Auftrag von ???? ??????????
> Gesendet: Sonntag, 14. April 2013 20:14
> An: Philippe
> Cc: interest at qt-project.org
> Betreff: Re: [Interest] Qt 5.0.2 speed and widgets
> 
> Yes, we are having same problem here. Same setup, AFAIK.
> 
> Don't know what's causing problem. 
> 
> Also, Mac OS has no noticeable speed regressions, it seems Windows-specific
> issue.
> 
> ???? ??????????
> 
> 14.04.2013, ? 21:55, Philippe <philwave at gmail.com> ???????(?):
> 
> > Compared to Qt 4.8.x, I experiment a very sensible reduction of speed 
> > in 5.0.2 when widgets are created or complex windows activated.
> > In Release mode this is "sort of acceptable",... maybe half speed.
> > But in debug mode, this is dramatically slower, up to 6x slower than 
> > in 4.8.3.
> > 
> > This is not a painting issue as the speed inside a window has been 
> > measured to be sensibly the same to 4.8.x (using ANGLE).
> > 
> > Anyone else sees the same? Any known reason for this?
> > 
> > Setup: Windows 7, Visual 2010, Qt 32 bit, *very* fast computer.
> > 
> > Philippe
> > 
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