[Qt-interest] Qt-4.2.2- CPU loading issues

[ARUN_KUMAR at denso-diam.com]

Thanks for reply.

The problem here is the project which I am doing is going on from last 2 
yrs. 
This project is into maintenance, and the management is not going to 
change the Qt version immediately but  may consider in future,
 As of now this is the loading issue, I am facing. 

I have done compiler optimizations also, but that didn't helped much.
Can anybody have any clues, on how to reduce loading based on profiling 
output.

Thanks & Regards,
Arun





<anders.bakken at nokia.com> 
09/21/2009 09:02 PM

To
<ARUN_KUMAR at denso-diam.com>, <qt-interest at trolltech.com>
cc

Subject
RE: [Qt-interest] Qt-4.2.2- CPU loading issues






4.2.2 is pretty darn old. I would recommend trying Qt 4.5.2 atleast since 
a lot of performance improvements went into 4.5. 4.6 might be good to test 
as well.

Anders
________________________________________
From: qt-interest-bounces at trolltech.com 
[qt-interest-bounces at trolltech.com] On Behalf Of ext 
ARUN_KUMAR at denso-diam.com [ARUN_KUMAR at denso-diam.com]
Sent: Monday, September 21, 2009 6:00 PM
To: qt-interest at trolltech.com
Subject: [Qt-interest] Qt-4.2.2- CPU loading issues

Hi All,

I am working with Qt-4.2.2 for my project. I am using stacked widgets in 
my project, where each screen has some data widgets (like labels, 
tableWidgets etc) to display.
As I am experiencing some CPU loading issues for my Qt project. I have 
done profiling to it and I have seen Qt is spending most of the time in 
blit_16_to_16 function.

Profiling Output:

CPU: CPU with timer interrupt, speed 0 MHz (estimated)
Profiling through timer interrupt
samples      %               symbol name
5655        15.6818         blit_16_to_16(blit_data const*)
1476        4.0931           qt_intersect_spans(QClipData const*, int*, 
QT_FT_Span_ const*, QT_FT_Span_ const*, QT_FT_Span_**, int)
1418        3.9322           blend_color_rgb16(int, QT_FT_Span_ const*, 
void*)
797          2.2101           QWidgetPrivate::sub 
tractOpaqueChildren(QRegion&, QRegion const&, QPoint const&, int) const
650          1.8025           miRegionOp(QRegionPrivate&, QRegionPrivate 
const*, QRegionPrivate const*, void (*)(QRegionPrivate&, QRect const*, 
QRect const*, QRect const*,
                                     QRect const*, int, int), void 
(*)(QRegionPrivate&, QRect const*, QRect const*, int, int), void 
(*)(QRegionPrivate&, QRect const*, QRect const*, int, int))

So my question is, is it normal for Qt to spend 15% of its time in 
blit_16_to_16 function?
Or do i need to focus on some thing else, please give me some addvice on 
this.

Thanks & Regards,
Arun.




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