[Interest] Qt Performance : QT Widget Application vs WPF

[Иван Комиссаров]

Hello. When you create a widget with no parent, it becomes a separate window. So, you're creating 200 (native) windows and then destroy them when you put a widget in a list. Creating native controls is a very slow operation.
Try passing a view as a parent for UserControl.
Next, what is real usecase? I haven't seen any applications with 200 forms in a list.

Иван Комиссаров

10 марта 2015 г., в 9:49, Chandralatha Harish <chandralathadc at gmail.com> написал(а):


> Hi All,
> 
> I was trying to evaluate QT vs WPF in terms of Memory , Performance , Window HAndles, User objects, GDI and so on..
> So built 2 identical looking controls in WPF and QT with all values harcoded.
> BAsically a usercontrol - which is "QFrame holding 3 Labels with text, 3 labels with Images, 3 combo box, "
> and created the usercontrol in a loop of 100, 200 ,1000 , 10000 and so on... with the button click on the main window,
> The code in QT is as follows...
> 
> void MainWindow::on_pushButton_clicked()
> {
> QElapsedTimer myTimer;
> myTimer.start();
> 
> for(int i=0;i<100;i++)
> {
> 
> QListWidgetItem *item=new QListWidgetItem(ui->listWidget);
> UserControl *row=new UserControl (0);
> item->setSizeHint(row->maximumSize());
> ui->listWidget->setItemWidget(item,row);
> }
>  ui->timeLabel->setText( QString::number(myTimer.elapsed())+ " ms");
> }
> 
> On Measuring the performance, with the above code in QT (vs WPF with very identical code in WPF)
> -> First of all in QT,I could notice a lot difference in performance measure between the debug build vs release build of QT( say if release build take 1.3 sec to create 200 controls debug build takes around 7 sec)
> --> On creating 100 and 200 user controls the performance measures of WPF were identical to performance measures of release build in QT.
> --> but on increasing the loop size, i noticed QT performance was pretty bad w.r.t to WPF.
> for 1000 UserControls- WPF took - 7sec( creation + render time) and 137 MB of memory
> while QT took - 15 sec(creation+render time) and 147MB of memory
> 
> for 10,000 usercontrols- WPF took - 79sec and 1 GB memory
> QT took - 22 mins for creation and rendering and 1GB of memory
> Note: Each UserControls Contains around 9 controls
> Can some one comment on
> -> Is QT Performance bad compared to WPF for huge number of controls?
> -> Is it the issue with the Rendering engine used by default. I'm using QT 5.4 64 bit Open source version of QT.
> -> the below states QT native rendering suffers with Performance issues - and Raster graphics to be usedhttps://kjellkod.wordpress.com/2011/05/22/moving-to-qt5-will-that-remove-qts-performance-issues-on-linux/ <https://kjellkod.wordpress.com/2011/05/22/moving-to-qt5-will-that-remove-qts-performance-issues-on-linux/>
> How to switch to Raster Graphics inQT 5? Understand that QApplication.SetGraphicsSystem has been deprecated in QT5.
> --> Is QT Quick better vs Widget application in terms of performance?
> 
> Thanks in Advance,
> Latha
> 
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