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Flickering and slow performance ubuntu 21.04

Posted: 16. Sep 2021, 07:57
by saledan
Hi all,
I have a macbook running osx 10.15.7 and virtualbox 6.1 I just updated ubuntu from 19.04 to 21.04
Now when I login into ubuntu every few (randomly) seconds I get a black screen just for a while.
It seems as slow flickering effect.
I updated guest addition but not solved the issue.

Also I have a performance issue, the system is very slow.

Up to version 20.04 (step before 21.04) it worked properly.

Please may you help me? In this way I cannot use the system

Re: Flickering and slow performance ubuntu 21.04

Posted: 16. Sep 2021, 17:45
by scottgus1
Start the VM from full power off, not save-state. Run until you see the problem happen, then shut down the VM from within the VM OS if possible. If not possible, close the Virtualbox window for the VM with the Power Off option set.

Please right-click the VM in the main Virtualbox window's VM list, choose Show Log. Save the far left tab's log, zip the log file, and post the zip file, using the forum's Upload Attachment tab.

Re: Flickering and slow performance ubuntu 21.04

Posted: 16. Sep 2021, 21:02
by saledan
Hi, thank you.
log attached.


I tried with WaylandEnable=false, or selecting xorg at login, but it doesn't work for me

Re: Flickering and slow performance ubuntu 21.04

Posted: 16. Sep 2021, 21:40
by saledan
Hi,
I found the issue for flickering. It's the graphic card selected on vm settings. Change from VBoxVGA to VMSVGA.
Now I have a resolution issue. on mac I use 1440x900 otherwise for me it's very high resolution (no good eyes :-/).
On previous configuration I didn't remember what I changed. Now I'll try with xrandr.

Now I have to increase performance. I'll try to add a CPU. Now I have 3, but I can add just one more CPU.

Re: Flickering and slow performance ubuntu 21.04

Posted: 16. Sep 2021, 21:55
by saledan
Resolution stuck at 2880x1800 I don't know how to change.
If I click on Display Settings menu, nothing opens.

Re: Flickering and slow performance ubuntu 21.04

Posted: 16. Sep 2021, 22:49
by granada29
You have overcommitted your RAM allocation. I suggest reducing to 4GB (currently it is set to 8GB but you only have 6.9GB available).

You could also try setting the Scale Factor to 200% in VirtualBox -> Preferences -> Display

Re: Flickering and slow performance ubuntu 21.04

Posted: 16. Sep 2021, 23:34
by saledan
display settings doesn't appear.
gnome-control-center wasn't installed (I don't know why). I installed it and fix with 200% scale as suggested.
Thank you
Anyway scale setting is not saved at reboot :-/

About Ram I don't understand. I reduced it to 4gb but no performance increased.
I free ram on osx, but again no success.

Re: Flickering and slow performance ubuntu 21.04

Posted: 17. Sep 2021, 01:16
by granada29
saledan wrote:display settings doesn't appear.
gnome-control-center wasn't installed (I don't know why). I installed it and fix with 200% scale as suggested.
Thank you
Anyway scale setting is not saved at reboot :-/
The Scale Factor setting is applied in the host VirtualBox Preferences - i.e. the VirtualBox app on your Mac. It appears you are setting it in your Ubuntu guest.

Re: Flickering and slow performance ubuntu 21.04

Posted: 18. Sep 2021, 21:25
by saledan
Yes sure, I applied it to ubuntu.
Scaling on virtualbox is not really good. Fonts are a little bit out of focus.
Scaling on ubuntu works fine and fonts are rendered sharp.

Anyway .. the main issue now is slow performance.
My guest pc is a MacBook Pro (15-inch, 2017) 2,9 GHz Intel Core i7 quad-core 16 GB 2133 MHz LPDDR3
I tried to enable 3d acceleration, but no performance enanched.
is Ubuntu 21.04 more heavy now than 19.04?

Re: Flickering and slow performance ubuntu 21.04

Posted: 18. Sep 2021, 22:01
by granada29
saledan wrote: My guest pc is a MacBook Pro (15-inch, 2017) 2,9 GHz Intel Core i7 quad-core 16 GB 2133 MHz LPDDR3
Just to get the terminology correct:
Your GUEST is Ubuntu
Your HOST is your MacBook Pro

I don't use Ubuntu so cannot comment on relative performance of different versions. However, my Debian Bullseye VM with KDE gives adequate/acceptable performance and no screen flickering with:

Linux Guest Additions installed
Video Ram 128MB
Scale factor 200%
Graphics Controller VMSVGA
3D Accel: disabled
GUEST resolution 1920x1080
No additional video scaling in the GUEST

Re: Flickering and slow performance ubuntu 21.04

Posted: 20. Sep 2021, 08:57
by saledan
granada29 wrote: Just to get the terminology correct:
Your GUEST is Ubuntu
Your HOST is your MacBook Pro
Yes sure!
granada29 wrote: I don't use Ubuntu so cannot comment on relative performance of different versions. However, my Debian Bullseye VM with KDE gives adequate/acceptable performance and no screen flickering with:

Linux Guest Additions installed
Video Ram 128MB
Scale factor 200%
Graphics Controller VMSVGA
3D Accel: disabled
GUEST resolution 1920x1080
No additional video scaling in the GUEST
ok thanks a lot!

Now I'm trying with gnome flashback

Re: Flickering and slow performance ubuntu 21.04

Posted: 20. Sep 2021, 22:03
by saledan
granada29 wrote:
saledan wrote: My guest pc is a MacBook Pro (15-inch, 2017) 2,9 GHz Intel Core i7 quad-core 16 GB 2133 MHz LPDDR3
Just to get the terminology correct:
Your GUEST is Ubuntu
Your HOST is your MacBook Pro

I don't use Ubuntu so cannot comment on relative performance of different versions. However, my Debian Bullseye VM with KDE gives adequate/acceptable performance and no screen flickering with:

Linux Guest Additions installed
Video Ram 128MB
Scale factor 200%
Graphics Controller VMSVGA
3D Accel: disabled
GUEST resolution 1920x1080
No additional video scaling in the GUEST

which is you mac?