Bug 183121

*** Bug 193759 has been marked as a duplicate of this bug. ***

I can confirm. Plasma and X are each competing for 100% CPU. I have a non debug backtrace. I'll try to include a debug once I find the time to compile debug packages:

#0  0xb7db63e6 in memcpy () from /lib/libc.so.6                                            
#1  0xa33e4008 in ?? ()                                                                    
#2  0xb6be4a74 in QX11PixmapData::toImage () from /usr/lib/libQtGui.so.4                   
#3  0xb6bd277b in QPixmap::toImage () from /usr/lib/libQtGui.so.4                          
#4  0xb6c05576 in QBrush::textureImage () from /usr/lib/libQtGui.so.4                      
#5  0xb6ca7a3b in ?? () from /usr/lib/libQtGui.so.4                                        
#6  0xb6ca8b80 in ?? () from /usr/lib/libQtGui.so.4                                        
#7  0xb6cad9d7 in ?? () from /usr/lib/libQtGui.so.4                                        
#8  0xb6c3adef in QPainter::drawPath () from /usr/lib/libQtGui.so.4                        
#9  0xb6c34aba in ?? () from /usr/lib/libQtGui.so.4                                        
#10 0xb6c37c33 in QPainter::drawRects () from /usr/lib/libQtGui.so.4                       
#11 0xb6c3a4f6 in QPainter::drawPixmap () from /usr/lib/libQtGui.so.4                      
#12 0xa8798cd3 in Image::paint () from /usr/lib/kde4/plasma_wallpaper_image.so             
#13 0xb7c0451d in Plasma::Applet::paint () from /usr/lib/libplasma.so.3                    
#14 0xb7158eba in ?? () from /usr/lib/libQtGui.so.4                                        
#15 0xb716426b in ?? () from /usr/lib/libQtGui.so.4                                        
#16 0xb7166628 in QGraphicsScene::drawItems () from /usr/lib/libQtGui.so.4                 
#17 0xb717445c in QGraphicsView::drawItems () from /usr/lib/libQtGui.so.4                  
#18 0xb7180d3e in QGraphicsView::paintEvent () from /usr/lib/libQtGui.so.4
#19 0xb6b5a582 in QWidget::event () from /usr/lib/libQtGui.so.4
#20 0xb6f361b3 in QFrame::event () from /usr/lib/libQtGui.so.4
#21 0xb6fd5ac4 in QAbstractScrollArea::viewportEvent () from /usr/lib/libQtGui.so.4
#22 0xb717f0af in QGraphicsView::viewportEvent () from /usr/lib/libQtGui.so.4
#23 0xb6fd80f5 in ?? () from /usr/lib/libQtGui.so.4
#24 0xb687f4ea in QCoreApplicationPrivate::sendThroughObjectEventFilters () from /usr/lib/libQtCore.so.4
#25 0xb6b0568a in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#26 0xb6b0ce44 in QApplication::notify () from /usr/lib/libQtGui.so.4
#27 0xb7797c8a in KApplication::notify () from /usr/lib/libkdeui.so.5
#28 0xb688039b in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#29 0xb6b62de5 in QWidgetPrivate::drawWidget () from /usr/lib/libQtGui.so.4
#30 0xb6d1cc85 in ?? () from /usr/lib/libQtGui.so.4
#31 0xb6b53b86 in QWidgetPrivate::syncBackingStore () from /usr/lib/libQtGui.so.4
#32 0xb6b5ad63 in QWidget::event () from /usr/lib/libQtGui.so.4
#33 0xb6f361b3 in QFrame::event () from /usr/lib/libQtGui.so.4
#34 0xb6fd65ba in QAbstractScrollArea::event () from /usr/lib/libQtGui.so.4
#35 0xb717e546 in QGraphicsView::event () from /usr/lib/libQtGui.so.4
#36 0xb6b056ac in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#37 0xb6b0ce44 in QApplication::notify () from /usr/lib/libQtGui.so.4
#38 0xb7797c8a in KApplication::notify () from /usr/lib/libkdeui.so.5
#39 0xb688039b in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
---Type <return> to continue, or q <return> to quit---
#40 0xb6880e58 in QCoreApplicationPrivate::sendPostedEvents () from /usr/lib/libQtCore.so.4
#41 0xb688102d in QCoreApplication::sendPostedEvents () from /usr/lib/libQtCore.so.4
#42 0xb68ab99f in ?? () from /usr/lib/libQtCore.so.4
#43 0xb4fb0288 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#44 0xb4fb3878 in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#45 0xb4fb39ea in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#46 0xb68ab5cc in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#47 0xb6ba4535 in ?? () from /usr/lib/libQtGui.so.4
#48 0xb687e929 in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#49 0xb687ed72 in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#50 0xb68810ef in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#51 0xb6b05527 in QApplication::exec () from /usr/lib/libQtGui.so.4
#52 0xb7eb2986 in kdemain () from /usr/lib/libkdeinit4_plasma.so
#53 0x0804858b in _start ()

I'm running KDE 4.2.4 on Qt 4.5.1 w/ an nvidia 7600gs using drivers 180.51 with archlinux binary packages

afaik, this is something that needs to be addressed in Qt; the scaling-and-painting is just too slow.

This still happens on qt-4.5.2. I'm running KDE from trunk using an nvidia 8600 GT (proprietary driver). Does this happens on every system, or it is a problem with specific hardware configs?

should this be marked as a upstream bug? i vaguely remember somebody of qt talking about fixing this in qt, anybody knows the status of this?

it's improved a bit in KDE 4.3, it will probably improve a bit more once Qt 4.6 is out. we may be changing how the activity overview is done in KDE 4.4 completely, however. hard to say when to close this bug for sure and where to put the most work into it. 

let's see what comes out of Tokamak 3 next week regarding activity switching first.

*** Bug 206224 has been marked as a duplicate of this bug. ***

from what i can see in trunk and with qt 4.6 this has improved quite a big. i'm closing this bug for now. Please reopen if this is still a issue for you in kde 4.4 (trunk) and qt 4.6

Created attachment 38608 [details]
The profiling report du with sysprof

Closing correctly.