[SOLVED] Poor 2D graphics performance in QT

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y.yemelyanov
Posts: 19
Joined: Sat Mar 12, 2016 12:01 pm

[SOLVED] Poor 2D graphics performance in QT

Postby y.yemelyanov » Tue Jan 24, 2017 12:22 pm

Hello,

We are trying out QT 5 application on VAR-SOM-AM33 (600 MHz clock). We are seeing very strange performance issues -
Create a simple QT Widget application with pre-generated form-window. Place 3-5 buttons on the form of a fairly large size 50x30 px or a bit larger.
Run on VAR-SOM-AM33. As soon as the app runs, the mouse cursor starts to lag pretty heavily. Shut the app down and the cursor moves ok.

I have found similar issue posted on TI forums - http://e2e.ti.com/support/arm/sitara_arm/f/791/p/534531/1958517

Have you seen these things on your side?

Thank you

fradensky
Posts: 41
Joined: Sun Nov 13, 2016 7:55 am

Re: Poor 2D graphics performance in QT

Postby fradensky » Tue Jan 24, 2017 12:35 pm

Hi,

What Yocto version are you using ? TI forum thread mentions rather old software.

Felix.

y.yemelyanov
Posts: 19
Joined: Sat Mar 12, 2016 12:01 pm

Re: Poor 2D graphics performance in QT

Postby y.yemelyanov » Tue Jan 24, 2017 3:05 pm

Hi Felix,

We are using Krogoth. Even the one from your FTP has this issue.

fradensky
Posts: 41
Joined: Sun Nov 13, 2016 7:55 am

Re: Poor 2D graphics performance in QT

Postby fradensky » Tue Jan 24, 2017 7:15 pm

Hi Yuri,

I did not notice the problem you describe when running QT example applications under MatrixGui. Sounds like an error in your application.

Felix.

y.yemelyanov
Posts: 19
Joined: Sat Mar 12, 2016 12:01 pm

Re: Poor 2D graphics performance in QT

Postby y.yemelyanov » Thu Jan 26, 2017 1:36 pm

Hi Felix,

Thanks for your reply.
Buit-in QT apps also have this problem, but because the window and/or the actual UI elements are small in size it is less noticable. If you look closely on the Calculator app, you can see how cursor is slowing down too. Perhaps you will start noticing this after watching the video below.

I have made a little vedio to demonstrate the effect:
https://www.youtube.com/watch?v=5dRDGzhcnn0

Note how mouse pointer is moving smoothly on the blank area of the window and lags over at controls. It's as if it is going through jelly. If you have more controls on the window, mouse becomes so laggy, it's unusable. CPU load is minimal though.

There could be no error in the example app in the vedio - we created a blank project, put the controls on the form and that's it, it is not doing anything else at all.

fradensky
Posts: 41
Joined: Sun Nov 13, 2016 7:55 am

Re: Poor 2D graphics performance in QT

Postby fradensky » Sun Jan 29, 2017 7:39 am

Hi Yuri,

I don't see this problem with calculator demo. Anyway, please try setting

export QT_QPA_EGLFS_NO_LIBINPUT=1

before starting your QT application.

Felix.

fradensky
Posts: 41
Joined: Sun Nov 13, 2016 7:55 am

Re: Poor 2D graphics performance in QT

Postby fradensky » Wed Feb 01, 2017 7:55 am

Hi Yuri,

Did you try setting QT_QPA_EGLFS_NO_LIBINPUT=1 ?

Felix.

y.yemelyanov
Posts: 19
Joined: Sat Mar 12, 2016 12:01 pm

Re: Poor 2D graphics performance in QT

Postby y.yemelyanov » Thu Feb 02, 2017 8:36 pm

Hi Felix,

Yes, tried this, but the result is unchanged. I tried compiling the app into Debug and Release, but that does not affect it. I also tried DVK dev kit as well as our custom board, different mice, different resolutions, nothing helps.

The only difference I found was setting all the elements to disabled (so they a re greyed out and don't work). If I do this, the mouse works fine. So it appears like the issue is with the default animation of a control highlight when a cursor is hovered over that control. I wonder if this is too heavy for a GPU...

y.yemelyanov
Posts: 19
Joined: Sat Mar 12, 2016 12:01 pm

Re: Poor 2D graphics performance in QT

Postby y.yemelyanov » Wed Feb 15, 2017 4:45 pm

Ok, I have some update on the issue. Basically, I don't think the problem is with any of our programming. The problem is either with QT itself or with hardware 2d graphics performance.

Here is an easy way to reproduce poor cursor speed on VAR-DVK:
1. From Matrix UI go to QT5 shortcut
2. Start "Deform" app
3. Try to move the mouse - the cursor is very sluggish.
4. Right click (notice how laggy is the popup window).
5. Click "Animation" to stop the animation.
6. Try to move the mouse now - notice how smooth it is now.

I am able to replicate this cursor performance with just genearl QT form with a few buttons on it as I showed above.

My question is -- is this sort of low performance expected or are my SOMs faulty? Is this a QT issue or PowerVR is THAT bad?!

fradensky
Posts: 41
Joined: Sun Nov 13, 2016 7:55 am

Re: Poor 2D graphics performance in QT

Postby fradensky » Thu Feb 16, 2017 11:35 am

Hi Yuri,

Our measurements show that slow mouse may be caused by Weston graphics server. Please try to stop Weston and run your application with eglfs plugin:

/etc/init.d/matrix-gui-2.0 stop
/etc/init.d/weston stop
qt-app -platform eglfs

Also please note the following patch that affects the rendering in deform application
http://arago-project.org/git/?p=meta-ar ... ch;hb=HEAD

Felix.


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