Lag spikes on desktop | Arch Linux Community | Page 1

torn moat Feb 23, 2023, 3:07 PM

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I'm seeing what look like lag spikes in KDE - I've got the KDE FPS counter enabled and can see paint times go up when there's a spike.

Looking at logs in yast, I see:
kwin_screencast: Dropping a screencast frame because the compositor is slow

I'm not sure that's the problem or a symptom though. I'm not doing anything intensive - I've got Firefox open, Discord and Dolphin. Sometimes I have a youtube video playing (and I've set the variable to force enable hardware decoding in Firefox)

I'm on OpenSUSE Tumbleweed, up to date. Running a 6900XT with amdgpu installed. I've got my CPU governor set to performance to see if that resolved the issue but it doesn't seem to. All effects and compositor settings should be default.

Using Wayland.

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Of note:
OpenSUSE does't have the patch Fedora does for Firefox. Hardware decoding is forced off it seems even with the variable set in about:config.

I've tried KWIN latency set to both smooth and balanced

swift field Feb 23, 2023, 3:16 PM

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@torn moat are you sharing or recording your screen?

torn moat Feb 23, 2023, 3:16 PM

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No

swift field Feb 23, 2023, 3:16 PM

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And when it exactly happens?

torn moat Feb 23, 2023, 3:17 PM

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Everything seems to just freeze for a second. If you're moving the mouse, it'll stop and then jump forward

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with the KDE fps counter turned on, I can see the "Paint Duration" spikes suddenly

swift field Feb 23, 2023, 3:19 PM

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But that happens when you have some program in background

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Or it also happens when you don't have opened any program?

torn moat Feb 23, 2023, 3:20 PM

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The latest time, I had open Firefox playing a video, discord, Dolphin.

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I'm trying to avoid playing video right now to see if it happens again or not

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Oh and yakuake running in the background (drop down terminal)

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I know that if I hover over firefox in the taskbar so that it peeks all open windows, I see a lag spike as that pops up - sometimes anyway. DIdn't do it just now. It might do it if I had a video playing?

swift field Feb 23, 2023, 3:23 PM

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Mm, rare, can you reproduce the problem but with dmesg -w in a terminal?

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So we can see its not a PCI-E problem or something like that

torn moat Feb 23, 2023, 3:24 PM

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Sure. Just leave that command running?

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hmmm, not seeing it yet. Wondering if I got a popup notification at the same time.

swift field Feb 23, 2023, 3:42 PM

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torn moat Sure. Just leave that command running?

Yes

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I guess you didn't see nothing special on there

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When the lag spike happens

torn moat Feb 23, 2023, 3:58 PM

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The lag spike hasn't happened yet - will leave that running

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Not sure if it's specific videos (4k60 vs 1440 etc)

#Lag spikes on desktop