Last update made everything slower

[VanessaDeagan]

Running 18.10 on my desktop and laptop.

One of the things I really notice in a UI is micro-stutter (especially when scrolling in Firefox).

Yesterday, things were running super quick and smooth, and there was minimum micro-stutter in Firefox.

This morning, after performing an update, the micro-stutter is (unfortunately) back.

[chimak111]

Install inxi and post the output of

inxi -Fxxxz

That information may help people help you.

Mine looks like this:

$ inxi -Fxxxz
System:    Host: dkb-KUBU-CC Kernel: 4.17.0-7-generic x86_64 bits: 64 compiler: gcc v: 8.2.0 
         Desktop: KDE Plasma 5.13.4 tk: Qt 5.11.1 wm: kwin_x11 dm: sddm 
         Distro: Ubuntu 18.10 (Cosmic Cuttlefish) 
Machine:   Type: Kvm System: QEMU product: Standard PC (i440FX + PIIX, 1996) v: pc-i440fx-bionic 
         serial: <filter> Chassis: type: 1 v: pc-i440fx-bionic serial: <filter> 
         Mobo: N/A model: N/A serial: N/A BIOS: SeaBIOS v: 1.10.2-1ubuntu1 date: 04/01/2014 
CPU:       Topology: Single Core model: Intel Core (Broadwell no TSX IBRS) bits: 64 type: MCP arch: Broadwell 
         rev: 2 L2 cache: 16.0 MiB 
         flags: lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 bogomips: 3984 
         Speed: 1992 MHz min/max: N/A Core speed (MHz): 1: 1992 
Graphics:  Card-1: Red Hat QXL paravirtual graphic card driver: qxl v: kernel bus ID: 00:02.0 
         chip ID: 1b36:0100 
         Display: x11 server: X.Org 1.20.0 driver: none unloaded: fbdev,modesetting,vesa compositor: kwin x11 
         resolution: 1280x720~60Hz 
         OpenGL: renderer: llvmpipe (LLVM 6.0 256 bits) v: 3.3 Mesa 18.1.5 compat-v: 3.1 direct render: Yes 
Audio:     Card-1: Intel 82801FB/FBM/FR/FW/FRW High Definition Audio vendor: Red Hat QEMU Virtual Machine 
         driver: snd_hda_intel v: kernel bus ID: 00:04.0 chip ID: 8086:2668 
         Sound Server: ALSA v: k4.17.0-7-generic 
Network:   Card-1: Intel 82371AB/EB/MB PIIX4 ACPI type: network bridge driver: piix4_smbus v: N/A port: N/A 
         bus ID: 00:01.3 chip ID: 8086:7113 
         Card-2: Realtek RTL-8100/8101L/8139 PCI Fast Ethernet Adapter driver: 8139cp v: 1.3 port: c000 
         bus ID: 00:03 chip ID: 10ec:8139 
         IF: ens3 state: up speed: 100 Mbps duplex: full mac: <filter> 
Drives:    Local Storage: total: 20.00 GiB used: 6.47 GiB (32.4%) 
         ID-1: /dev/sda model: QEMU HARDDISK size: 20.00 GiB speed: <unknown> serial: <filter> rev: 2.5+ 
         scheme: MBR 
Partition: ID-1: / size: 19.56 GiB used: 6.47 GiB (33.1%) fs: ext4 dev: /dev/sda1 
Sensors:   Message: No sensors data was found. Is sensors configured? 
Info:      Processes: 135 Uptime: 20m Memory: 3.85 GiB used: 807.1 MiB (20.5%) Init: systemd v: 237 runlevel: 5 
         Compilers: gcc: N/A Shell: bash v: 4.4.19 running in: konsole inxi: 3.0.20 
dkb@dkb-KUBU-CC:~$

Also, how did you "update"? Was it via Discover, Muon or the command line?

I like using

sudo apt-get update

followed by

sudo apt-get dist-upgrade

I'm running Kubuntu 18.10 in a VM (qemu/kvm with 4GB RAM and one CPU core) and don't see any adverse effects from today's mega update.

Edit: I'm guessing there'll be a lot more updates coming through in the near term, feature freeze being August 23, now that the Qt issue (whatever that was) has been overcome.

[GreyGeek]

Before you begin tweaking things or making changes give it some time. Since others are not having the problem you mentioned perhaps it is something related to your particular setup. The devs have, no doubt, more updates coming down the pipe and I suspect that future updates may resolve your problem without you doing anything to your system. Just writing from my past experience.

[VanessaDeagan]

Thanks for the replies. Sorry that my initial post was quite vague and lacking in details, but there's a reason for that - this is a "user experience" issue, and one that can be quite subjective and very difficult to articulate. Here's one way to test for it:

1. Open Google in Firefox.
2. Click on the "Images" link.
3. Perform an image search for something (e.g. "Linux").
4. Middle-click on a blank space somewhere near the middle of the image results to activate auto-scroll.
5. Mouse the mouse pointer about 1cm below the auto-scroll circle.
6. Let go of the mouse to allow the page to scroll downwards slowly.
7. Observe the page closely as it's scrolling downwards.

For me (on an Core i7-4790 with an AMD RX560 with 4GB of RAM - and also on a laptop with Core i7-6700u and Intel HD 520 iGPU) there is frequent "micro-stutter" (I'm not sure what else to call it - perhaps "judder"?). Prior to my post, this wasn't there (on my desktop and laptop) - it scrolled perfectly smoothly and fluidly.

The title of my post is probably misleading - when I mentioned "things are slower", I mean specifically with scrolling in Firefox on certain pages (the example I've given above it just one example).

I've tried several things to try and get it perfectly smooth again, like setting layers.acceleration.force-enabled to true and using Wayland, but have not had any success.

@chimak111 - I very much doubt running Kubuntu 18.10 in a virtual machine would be a reliable way of testing this particular issue (I'm not even sure if it's possible to get Kubuntu running with hardware acceleration in a VM?).

Scrolling still works, it's just not working are smoothly as it was before I updated. It's by no means unusable, but the "glitches" (micro-stutter) is annoying (it will probably bother some people more than others).

I've also noticed the same "stutter" occurring sometimes with Wobbly Windows enabled.

[jlittle]

FWIW, I'm on bionic (i6700, using its graphics) and the jerky scrolling affects me too. I've no idea if this has changed recently; I rarely scroll slowly. I tried turning off the compositor with alt-shift-f12 but that made it worse, a kind of flashing effect.

[chimak111]

AFAICT, OP didn't explicitly say anything about using VM's. I caused the confusion with my post

I suspect OP is running on bare metal and if that's true it's very brave.

[claydoh]

AFAICT, OP didn't explicitly say anything about using VM's. I caused the confusion with my post

I suspect OP is running on bare metal and if that's true it's very brave.

Heh, my fault totally. I read this as the OPs config, I have been working too long today at the screen, nearly 6 hours(!?!), on top of my day job today. So that post is useless, other than the usual "It is A PreRelease So Expect This Sort Of Thing Regularly As Drivers and Kernels Are In Flux As Usual" caveats, with the additional "Spectre and Meltdown Fixes are drastically reducing cpu performance that Intel tried to gag linux benchmark tests results being shown" as being a possible additional culprit.

https://www.zdnet.com/article/intel-...s-new-license/

[VanessaDeagan]

Firstly, yes, I'm running on bare metal. I only use VMs for headless (server) Linux.

Secondly, I have found something that makes scrolling perfectly smooth (or as close to perfectly smooth that I've seen on Linux desktop):

Edit ~/.config/kwinrc and under the [Compositing] section add:

MaxFPS=75
RefreshRate=75

I have also noticed that this is also an issue on Kubuntu 18.04 (so it's not unique to 18.10). Just before I posted my first post in this thread, the issue wasn't there. I have no idea what's causing this issue (the "micro-stutter"), and I have no idea why setting my refresh rate to 75 resolves it (because all my monitors at 60Hz). Could it be possible that the compositor is not picking up the correct refresh rate?

I have used the above settings for quite some time now and have not experienced any side effects or extra battery drain.

Seems very odd.

[VanessaDeagan]

FWIW, I'm on bionic (i6700, using its graphics) and the jerky scrolling affects me too. I've no idea if this has changed recently; I rarely scroll slowly. I tried turning off the compositor with alt-shift-f12 but that made it worse, a kind of flashing effect.

Thank you for confirming it's not just me (I'm sometimes overly sensitive to such user-experience issues). I have a feeling this is an issue that will effect some more than others, but once you've had "smooth", you really don't want to go back (and scrolling in Firefox is something I do a lot).

Please see my post above - if you could try that out and post back here if it works for you, that would be very useful (I forgot to mention that I needed to log out and log back in again after adding those two lines).

[jlittle]

Please see my post above - if you could try that out and post back here if it works for you, that would be very useful.

Yes, I've made the changes and firefox scrolling is now smooth. To notice I have to enable smooth scrolling and autoscroll in Preferences.

once you've had "smooth", you really don't want to go back (and scrolling in Firefox is something I do a lot)

Well, I prefer fast to smooth. I use a Logitech mouse that I can unhitch the wheel from its detent mechanism and spin it freely; I often flick my finger to spin the wheel and race up or down, like a vertical-only trackball. I'm not sure, but I think with the kwinrc changes my rapid scrolling (I just timed 3,000 lines in 4 seconds in a syntax-coloured gvim window) seems nicer. Sometimes I'm watching for something as the display blurs past, ready to brake the wheel when I see what I'm looking for, and that felt better.

[VanessaDeagan]

Thanks for trying it out - I'm really glad it's not just me. There's definitely an issue with refresh rates in Kwin. I'll file a bug report, but it's difficult to qualify/quantify such an issue (as mentioned before, some people simply don't notice such things).

Well, I prefer fast to smooth.

They're not mutually exclusive