Poor performance in Plasma 6.8

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1

Due to the various issues I have had since the release of Plasma 6.7 and the update to kernel 7, I have not had the ability to do my usual benchmarking. The general trend over the past few years has been a constant improvement in performance. Not this time.

I had notice that my system seemed a bit sluggish after the update to 6.7, and there was no noticeable improvement with 6.8. So I ran my suite of tools and sure enough performance is reduced by a whopping 20%! Apps that rely on OpenGL and Xwayland are particularly hard hit.

Now, I realize that my rig is aging, and that people with newer high end machines may not notice this decline, but given the state of the hardware industry and the absolutely insane cost for new parts (sorry I refuse to pay 1000 dollars for a GPU that should cost 200, or 400 for a mobo that should cost 80, or 500 for a 10tb HDD that should cost 100 - I wont even talk about the silly price of RAM - it seems to me that a renewed focus should be put toward performance optimization.

This is disappointing to see. We saw many announcements about how Kernel 7 was supposed to improve performance… but it seems it has not.

I hope that the devs for Plasma, Wayland, and Xwayland look toward performance tuning over the next few months and not a mad scramble for “features” nobody is asking for. Many of us are not going to be upgrading any time soon. We use Linux because it is supposed to be high performance on humble equipment.

2

It seems you have had some issue for a while so I don’t know how you can attribute it to Plasma 6.8

This is not a KDE issue, and may well be specific to your hardware if you are seeing degraded performance. I suggest sticking to a LTS kernel if the 7x line is not working for you.

It often is, but as hardware improves and features are added software needs to keep up and use those features. It would be unreasonable and counter productive to ignore them.

I’m using Plasma on various hardware, a 2018 laptop, a raspberry pi 5, and a desktop from 2012 and they have all had performance increases with newer releases. But I also don’t expect newer features to necessarily support or run optimally on my old hardware.

3

Plasma 6.8 and Linux kernel 7 works fine with my Intel 2th generation Core i7, it’s possibly problem caused by your linux distribution or some lagging software…

4

tbh not knowing your system specs, I suspect a place to look at may be a kernel/driver problem rather than Plasma, considering that OpenGL seems to be the main symptom.

Maybe you are using software rendering instead of hardware because of some kernel or driver issue? That would definitley explain such a significant drop in graphics performance.

A quick way to tell is to see what KInfoCenter shows for the Graphics Processor. If it says llvmpipe, you are using software rendering instead of the GPU.

My semi-old HP business class “mini” pc with a low-power version of the Intel i5 from 2017, I have not noticed any drops in performance or anything, with its intel graphics, over the past three years I have been using it.

5

I knew this day would come. I have frozen all the updates to KDE Plasma packages. 6.7.5 is where i stand right now. I have been avoiding wayland for a long time now. I was using the “plasma-x11-session” to log into an X11 session. Not because i have some personal vendetta against wayland, the reason is much simple. My ghetto rig is too weak to handle it. There is a huge performance gap (at least for me) between using x11 and wayland and that gap is magnified when you are on a relatively old/weak rig.

I do “love” KDE plasma. Years ago, when i was a linux noob (still am), i have tried many desktop environments and i have decided that KDE was the de for me. Never used anything else. I still love it and i’d recommend it to anybody who wants the whole package, beauty and functionality. But currently, think i am at a crossroads. Because i will either bite the bullet/wallet and pay the ferryman or just switch to a lighter desktop environment who promises to keep supporting X11. I agree with you about everything being “ultra-expensive” right now. If i had paid the asked amounts for a mid-tier machine, i’d feel ripped off really. The picture is even bleaker if you are living in a third world country like me. The AI race have skewed the whole economy of computing. I do feel like this is just the beginning. And i am not against AI, i do think it will change humanity. Anybody who watched Star Trek TNG S01E17 would understand why.

Anyway, even though i don’t want it, my plan is to keep as much QT apps as possible, even dolphin, and switch to a lighter desktop environment that will support X11 for the foreseeable future. XFCE or MATE probably.

6

Have you tried Wayland on your rig? I have run Plasma 6.7.5 with Wayland on a 2008 Dell XPS with an Intel Core 2 Duo at 2 GHz, and, turning of the heavier effects, it works fine.

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I have also been monitoring message from people complaining about massive performance hits with Wayland, and often it is not Wayland’s fault at all, but misconfigured systems, problems with drivers, or :check_box_with_check: Other.

7

:100:

it is the worst time to happen that x11 was skipped for wayland-only. a lot of older ngreedia cards don’t work with wayland and the users face the fact that their gpu are obsolete electronic trash. that’s sad to see. wayland has it’s arguments but the development still lags and will take a long time until wayland is a really successor for x11. eleminating problems by creating new problems is no invention. wayland is the new era but it is not the holy grail as promised.

8

So use the LTS version of Plasma. You get 3 more years of X11, plenty of time to put your stuff in order, one would think.

But it is absurd and dare I say even a teeny bit selfish to ask that the volunteers at KDE support a platform that has not released a new version in 12 years. Our resources are very limited and we have to invest time in stuff that have a future.

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Yes, i have tried to switch to wayland more than once, booted into wayland sessions many times over the last two years, and i should say, it is not as bad as it was before. It certainly feels snappier than before. I actually think that KDE Plasma is probably the best adopter of wayland when it comes to it. But still, it is not as buttery smooth as it is in X11 in my case. And even though on first boot, it feels snappy yes, but things pile up on wayland, unlike on X11. As you open windows and apps, you lose responsiveness. And i understand, this is not Plasma’s fault, that is because i am clinging on to some old hardware. I should update :slight_smile: And realisticly, as somebody else has put it (rather erroneously), Linux is definitely still fast and high performing on older hardware, when it comes to what Linux actually is. Apples and oranges. If you stay on the terminal, and go desktop free, Linux would probably work on a calculator hardware. Linux is not the issue here. We should separate Linux core itself from the graphical interface implementations. The choice to go with wayland affects the graphical, be it the desktops or other GUI apps, and we should understand that the choice was made to make app development easier on the devs, as i understood it, working on ancient X11 code for modern computing demands was too much work. Yes, computing has to go forward and things will get more power/resource hungry, as we see with the advent of AI. So i am not pointing fingers, as neither should any of us. That is the way it is.

11

sorry but that’s too simple. a lot of users do have more needs as an old lts-kubuntu ! i don’t blame you or anyone and agree that limited resources force to skip parts of the distros like x-11. BUT i was always aware that skipping x11 will be a mess if wayland isn’t really competetive to x11 and this happens now. first, a lot of users still hang on older ngreedia cards or laptops with hybrid-gpu’s that have to use x-11 to run their hardware properly and second the business related server-infrastructures with a lot of remote server-client-systems that also still depend on x-11 cause the applications used need x-11 and there’s no proper replacement on wayland. wayland might be working on a usual desktop (with hick-ups) but it is not as good neither reliable as it is promoted. that’s fact. and btw. i’m sitting here actually at two different distros run in vm’s that are heavily broken through the upgrade to 6.8 and waste my weekend-time to fix it. thaanks …

12

Th solution seems simple to me and it boils down to “don’t upgrade then”. Upgrading implies changes. You don’t want those changes? Don’t upgrade. Nobody is forcing you to. This is not Windows.

X11 hasn’t been upgraded in any significant way for 12 years. You should be happy hanging on to Plasma 6.7 at least that long.

13

I’m still on 6.7.5, I’m waiting for 6.8.2 or 6.8.3 to upgrade, one great advice I got here is to disable all effects (especially blur which slows animations) and set animation to instant, you also disable night light, then disable any ICC or EDR or HDR in display settings and set color accuracy to efficiency, you will feel the desktop become more responsive.

14

Yes, I have tried Wayland. I have been testing Wayland as it has matured for years and I have been exclusively running Wayland on Neon for the past year. The effects still run fine. I run a whole pile myself including wobbly windows, slide back, and so on. I also use Cover switch for the task switcher animation. I notice that it, and the start menu were a bit slow to respond and sluggish, yet they responded instantly a few days ago with 6.7.5.

I tested the performance against Plasma 6.6.5 and Kernel 6.17, Plasma Plasma 6.8 on Kernel 6.17 and Kernel 7 both.

The difference between Plasma 6.6.5 and Plasma 6.8 running the same kernel is ~20%. Given that X11 is not supported, there is no way to determine if shows the same slowdown, but the slowdown did not exist in either X11 or Wayland with Plasma 6.6.5 as of a few days ago. So, by process of elimination the slowdown is not the fault of the hardware, drivers, or kernel as they are all consistent (I did run Kernel 7 with 6.7.5 for a while and did not notice any performance issues, but I did not benchmark it so I do not have direct numbers to compare). It is perhaps a problem with Neon, a problem with Plasma/Kwin, or a problem with Wayland/Xwayland. It may have started with Plasma 6.7, but it for sure exists in 6.8.

What I may do is install the new Kubuntu 26.10 which is running Plasma 6.7.5 to see if the slowdown does in fact exist in that version… but it is not running the same kernel (it uses 7.3 I believe) or libs, so it might not be a fair comparison. However in the past Kubuntu and Neon have both been equal in performance, so I expect I might see a difference there too if one exists. I will let you know.

15

This right here. Eye-candy is… well, candy. It has no nutritional value. You don’t need it to be able to use your computer. If your machine is slow because it is underpowered or old, it is the first thing you have to get rid of and not look back.

16

We have one old laptop at home similar to the one you shown Acer extenza with intel dual core T4400, it was running Wind 7, did you manage to use it with night light enabled? my little sister is using it to write her side projects at school and also easily read some pdfs on its screen bigger than her phone, the problem is that the time usage is mostly at night when she comes back from school, so for now I just minimize the laptop brightness to 50% and let two bulbs power on in her room, but I would love to enable light night to make it easy for her eyes while using it.

17

Nonsense. You are the communications officer? Yikes. That is the single worst attitude I have ever seen expressed in 35 years of using Linux. Basically you just said “fsck ya”. That is not a good look for KDE. Seems arrogance has become part of KDE since the John Riddell debacle. My machine is MORE than powerful enough to run Plasma with all the candy. Any machine made in the past 15 years is more than powerful enough.

Performance bottlenecks can be and often are introduced without intention. What you just did was effectively the same as victim blaming. Plasma 6.8 has a performance issues that need to be found and addressed. This is reality. Accept it. Stop passing the buck. This is Linux, not Windows.

18

If you’re after performance, maybe test out a different distribution. Under the new versions of KDE on Neon is whatever the Ubuntu project ships for their LTS base, which is not necessarily the highest-performance selection of components or configuration.

One person not valuing a particular feature doesn’t make it valueless.

The promise from developers of Linux/free and open source software is the freedom. If your desire is maximum performance on minimal hardware, then given it sounds like you have already set up some methods for testing performance, contributions to help identify bottlenecks in code and optimize them would be welcome, I’m sure.

19

TL;DR performance issues happen even on more powerful systems, devs(?)/community managers being dismissive for no reason

First time Linux user (CachyOS/KDE Plasma) since September here. Enjoying it so far, but this update has definitely made me rethink how often I update things. I have an RTX 5070 Prime OC, Ryzen 7 7800X3D with 32 GB RAM (Corsair Vengeance 6000 MHz CL30). So not the highest of ends, but definitely not a system I expect UI lag on (turned off fancy OS effects and animations, so called “eye-candy”, for accessibility reasons), or glaring performance issues on things that don’t even put a dent in system resources.

And yet, since Plasma 6.8, I’ve had some websites experience choppy/laggy UI animations (e.g. WhatsApp web scrolling sometimes, other sites when collapsing/expanding UI panels). To be fair, it is a dual-monitor setup (main: 160 Hz 4k monitor, secondary: 60 Hz vertical 1080p monitor), so at first I wrote it off as my eyes getting used to the higher refresh rate and now everything on my 60 Hz monitor will feel choppy. But no, as I one-time booted into a 6.7.5 snapshot and the problem was gone. Before that, I tried rolling back a recent NVidia driver + kernels (that dropped somewhere around 6.8 release) with no results.

I also thought it might’ve been because of Xwayland. I use it in Firefox for the GTK file picker because KDE’s portal file picker wants to wait until everything in a folder is loaded before I can click Save… Yes, GTK is available on Wayland, but for some reason it has the Cancel and Save buttons on the top left and top right?? Thus switching to Xwayland so I can set the buttons on the bottom right as god intended. In any case, this issue was not there in the 6.7.5 snapshot (nor do I remember it being an issue before 6.8).

Even if it were, running my QEMU/KVM Windows XP VM under Plasma 6.8 on Wayland also became painfully slow. To the point I had audio crackling when the XP logon jingle plays as the VM struggles to load, and having floaty mouse movements when even a crumb of animation plays (like Start menu buttons highlighting). Funnily enough, I decided to run virt-viewer with env GDK_BACKEND=x11 and now it works even better than when I used the normal virt-manager route on 6.7.5 (animations were choppy then too, but again I wrote it off as “trying to emulate old Windows on Linux” or some such). I did try to roll back QEMU to a previous version before the temporary switch to Plasma 6.7.5, and that didn’t solve it. I’ll note that I gave my XP 4 CPU cores and 8 GB RAM to work with. Using VGA graphics to play Zeus: Master of Olympus (QXL causes some mouse iffiness and probably not the place to get into).

Now, I get that rolling back to a previous snapshot changes more than just Plasma, but how much could the stack realistically have changed to cause such performance drops basically overnight? Especially when it’s not just me, as you can see from many reports on Reddit and other forums after 6.8. At some point you gotta ask if it’s that far-fetched to suspect a regression in the update than just dismissing it as “misconfigured systems, problems with drivers, or :check_box_with_check: Other.”

Also, I understand FOSS projects can be thankless/devs being overworked/not having resources to test on different builds/etc. But the solution isn’t to go “just don’t upgrade bro,” or “software freedom bro just use something else” towards people using your discussions platform to, well, discuss the issues they’re having. Particularly as a supposed “communications officer” and “Leader” (of whatever that may be).