Comment 10 for bug 1973434

@mruffel:
interesting, I am right now already at 5.15.0-37-generic from:
APT-Sources: http://de.archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages

I gave up with custom Kernels as it seemed they provide no clear improvement better then running the ubuntu package with iommu turned of as you recommended.

The last I tried was 5.18.1, but that doesn't work with the virtualbox dkms stuff which I depend on for work. I assume this wont better with 5.19, but i can try later.

I cannot say for sure if / how much of the problem existed in 21.10 because my usage scenario changed around the time when I updated - a new work project, more videocalls, and I am traveling and use the laptop more for media consumption as youtube and videos like this:
https://www.zdf.de/gesellschaft/markus-lanz/markus-lanz-vom-7-juni-2022-100.html

I had twice weekly videocalls with Teams in the browser which drove the CPU up and the fans on, but did not stutter to a point of being impossible.
But now I (try to) use Zoom, every day, and it's basically not possible - I have to use my (twice as old and much weaker mobile CPU) windows tablet for this.

I cannot "easily" start a full clean install as I need the machine for daily work, and setting everything up from scratch takes some while - but I will try to get a second disk to be able to do it but keep the exiting install to work as good as it is. I might be able to restore a pre-update state of my system into a free logical volume and run this. Will see how far i get!

It might very well be that I have multiple problems at once and every one of them contributes a bit to the poor performance I see, also because multiple changes seem to lead to slightly better behaviour each:

* turning iommu off makes things from extremely unsmooth to nearly acceptable
* turning intel_boost off makes things a bit better and acceptable
* moving from gnome to lxde gets me even pretty stutter free video(but not the UX I want...)

It could be a combination of kernel / graphics library / gnome(-shell)...

OR it could be *only* a kernel thing, but slightly suboptimal behaviour of graphics libaries and gnome.

E.g. gnome-shell has a lot of short cpu load peaks on a single core, which should normally not block everything else but maybe can lead to video stuttering when process/IO management and scheduling are wrong in the first place...

I'll keep testing and experimenting when I have spare time and report any findings here...