[solved] Qt apps behave unresponsively

orschiro · 2013-12-04 08:55:58

Hi there,

I have a very serious issue here with my Qt apps.

Their GUIs are very unresponsive and show all few seconds very annoying lags. For instance when I am typing text, I see the text being written about a second later. When I select text, I see the text being highlighted about a second later. And so on.

I experienced this unresponsiveness in Skype, Qtconfig, Virtualbox menus but not the virtual machine itself, and Sublime Text 3. The latter is interesting because as far as I know, it is not a Qt app.

Thus I am not even certain whether this is a true Qt app problem. All my GTK apps which I am running on my Openbox only system perform fine without any lags.

The journalctl logs don't show anything of interest. Thus I have no idea where to start looking for the error.

What could cause it - any ideas?

Last edited by orschiro (2013-12-23 16:30:55)

Minsc · 2013-12-04 10:50:03

I would run top and iotop and see what is hogging cpu/disk when it happens, that should help you narrow it down for a start.

orschiro · 2013-12-04 10:57:24

Skype and htop (sorted by CPU): http://i.imgur.com/IKFUhaK.png

Nothing special I can see.

And here the output of sudo iotop: http://i.imgur.com/UjqBga7.png

Minsc · 2013-12-04 11:02:09

Looks fine - where those screens taken when skype was being unresponsive? I meant re-create the problem, then watch iotop/top to see if anything is strange.

orschiro · 2013-12-04 11:07:58

This hanging problem appears periodically every few seconds. When observing iotop/top while for instance Skype is running, I do not see any special peaks. Just as you have already seen in the screenshots. Everything appears to be ok.

What else could cause such hangs and why not in GTK apps such as Chromium, Zotero, Thunar?

Minsc · 2013-12-04 11:10:48

It could be several things - I notice you're running on x86_64 so it could be one of the 32bit libs that skype uses or even your X driver.

orschiro · 2013-12-04 11:14:09

But then why does it happen in qtconfig-qt4, Virtualbox and Sublime Text 3, too?

Interestingly, when I run all these applications from the command line, then I do not see any error messages either.

x33a · 2013-12-04 12:50:15

Try downgrading your graphics driver and see if anything changes.

Minsc · 2013-12-04 14:35:19

What driver are you using for X? If you're using vesa, switch to the appropriate one for your card or try another alternative: https://wiki.archlinux.org/index.php/Xo … stallation

orschiro · 2013-12-04 18:58:55

@Minsc

No vesa here:

~ $ pacman -Q | grep xf86
lib32-libxxf86vm 1.1.3-1
libxxf86dga 1.1.4-1
libxxf86vm 1.1.3-1
xf86-input-evdev 2.8.2-1
xf86-input-wacom 0.23.0-1
xf86-video-intel 2.21.14-2
xf86dgaproto 2.1-2
xf86vidmodeproto 2.3.1-2

I will try downgrading xf86-video-intel.

Apart from that I am using the following Xorg config as I have a relatively old GMA 4500 which does not benefit from SNA.

~ $ cat /etc/X11/xorg.conf.d/20-intel.conf 
Section "Device"
   Identifier  "Intel Graphics"
   Driver      "intel"
   Option      "AccelMethod"  "uxa"
EndSection

orschiro · 2013-12-04 21:19:44

OK I downgraded xf86-video-intel but things remain unchanged.

~ $ downgrade xf86-video-intel

The following packages are available in your cache:

    1)  local              xf86-video-intel-2.21.15-1-x86_64.pkg.tar.xz
    2)  local              xf86-video-intel-2.21.14-2-x86_64.pkg.tar.xz [installed]

please choose a version, [s]earch A.R.M or [q]uit:

Any other ideas?

x33a · 2013-12-05 05:46:57

Maybe try clearing ~/.kde4 directory.

orschiro · 2013-12-05 05:50:06

@x33a

I don't have a ~/.kde4 directory. I also created a new test user but the same happens there. Could it be a dbus or systemd-related issue?

x33a · 2013-12-05 05:56:57

I don't use systemd myself, so I am not sure. Usually the video driver is suspect in such cases. Maybe you should open a bug report on the bug tracker.

orschiro · 2013-12-05 12:01:13

Bug report here: https://bugs.archlinux.org/task/38021

orschiro · 2013-12-13 07:39:12

I could further narrow down the problem. Interestingly the apps mentioned above behave correctly when launched within Gnome. So, Gnome must launch something that cause the apps to behave smoothly. I am almost certain it has something to do with the gconf or dconf settings which Qt needs but which are not loaded on Openbox.

To better compare both systems, I completely deleted all personal gtkrc files and configs.

But still, when launching Gnome, a different (the correct) icon theme (Faenza) is used. See this screenshot from Virtualbox:

http://i.imgur.com/WqFe6Ug.png

When launching Virtualbox in Openbox, a different (the Qt icons) icon theme (the Qt icons?) is used. I suspect that this is somehow causing troubles. See this screenshot:

http://i.imgur.com/iBRKMhD.png

What is doing Gnome differently than Openbox in that respect?

orschiro · 2013-12-23 16:30:46

I finally found the cause of the issue. non-GTK apps were not lagging on Cinnamon or Gnome not because of GTK settings but enabled composting. That is, when I run Openbox with compton, then these applications do not lag anymore!

Does anyone have an idea why just non-GTK apps require composting but GTK apps are running nicely without?

aagavin · 2015-07-30 12:06:15

orschiro wrote:

I finally found the cause of the issue. non-GTK apps were not lagging on Cinnamon or Gnome not because of GTK settings but enabled composting. That is, when I run Openbox with compton, then these applications do not lag anymore!
Does anyone have an idea why just non-GTK apps require composting but GTK apps are running nicely without?

Ok running composting also seemed to solve my problem. Not sure why this is an issue.

WorMzy · 2015-07-30 14:05:05

Welcome to the Arch Linux forums, aagavin. Please take a moment to read through the forum etiquette, in particular the section regarding necrobumping.

Closing.

Arch Linux

#1 2013-12-04 08:55:58

[solved] Qt apps behave unresponsively

#2 2013-12-04 10:50:03

Re: [solved] Qt apps behave unresponsively

#3 2013-12-04 10:57:24

Re: [solved] Qt apps behave unresponsively

#4 2013-12-04 11:02:09

Re: [solved] Qt apps behave unresponsively

#5 2013-12-04 11:07:58

Re: [solved] Qt apps behave unresponsively

#6 2013-12-04 11:10:48

Re: [solved] Qt apps behave unresponsively

#7 2013-12-04 11:14:09

Re: [solved] Qt apps behave unresponsively

#8 2013-12-04 12:50:15

Re: [solved] Qt apps behave unresponsively

#9 2013-12-04 14:35:19

Re: [solved] Qt apps behave unresponsively

#10 2013-12-04 18:58:55

Re: [solved] Qt apps behave unresponsively

#11 2013-12-04 21:19:44

Re: [solved] Qt apps behave unresponsively

#12 2013-12-05 05:46:57

Re: [solved] Qt apps behave unresponsively

#13 2013-12-05 05:50:06

Re: [solved] Qt apps behave unresponsively

#14 2013-12-05 05:56:57

Re: [solved] Qt apps behave unresponsively

#15 2013-12-05 12:01:13

Re: [solved] Qt apps behave unresponsively

#16 2013-12-13 07:39:12

Re: [solved] Qt apps behave unresponsively

#17 2013-12-23 16:30:46

Re: [solved] Qt apps behave unresponsively

#18 2015-07-30 12:06:15

Re: [solved] Qt apps behave unresponsively

#19 2015-07-30 14:05:05

Re: [solved] Qt apps behave unresponsively

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