Terminal lags (low FPS) the whole desktop when fast output

[Jean-Louis Dupond]

Hi,

When using Wayland and gnome-terminal, the performance/fps of the whole desktop is real low when gnome-terminal outputs alot of data.

This happens when you cat some logfile for example, or do a tail -f on a quickly growing file.
The whole desktop feels sluggish then.

This is only the case on Wayland. on X-Server it goes perfectly!

[Jean-Louis Dupond (dupondje)]

https://bugzilla.gnome.org/show_bug.cgi?id=778926 might be related

[Daniel van Vugt (vanvugt)]

This is a known issue for software-rendered windows that update rapidly. There are several reasons for it so also several possible solutions...

* GTK 3.x is software-rendered, so rapid window redraws that require uploading new frames to the GPU from the CPU may be slow. This is mostly fixable by changing GTK to hardware rendering (coming in GTK 4.0).

* Wayland lacks 2D acceleration options that Xorg has. However those could plausibly be emulated by modifying the GTK 3.x code in theory.

* The EGLNative platform (that used by "Wayland" sessions) in Mutter/Gnome-Shell is generally slower than the X11 platform. It doesn't have to be. It's just a younger less mature platform, which we're trying to improve. Fixes for this would come in the 'mutter' project.

[Jean-Louis Dupond (dupondje)]

The following commit fixes the issue for 90%:
https://git.gnome.org/browse/vte/commit/?id=809e79770

its not as fast as it was on X, but its useable now :)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.