| Summary: | Desktop session slows to a crawl on multi-monitor setups while running VR | ||
|---|---|---|---|
| Product: | [Plasma] kwin | Reporter: | Daniel Well <dantheman22505> |
| Component: | performance | Assignee: | KWin default assignee <kwin-bugs-null> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | 0xdeadcade, foley2431, jared, nate, xaver.hugl |
| Priority: | NOR | ||
| Version: | 6.2.2 | ||
| Target Milestone: | --- | ||
| Platform: | Arch Linux | ||
| OS: | Linux | ||
| Latest Commit: | https://invent.kde.org/plasma/kwin/-/commit/2d543f4a790b93c465caf2eb3504cb2915477924 | Version Fixed In: | 6.2.4 |
| Sentry Crash Report: | |||
| Attachments: | Bisect log performed on 2024-10-30T18:00:00-05:00 | ||
|
Description
Daniel Well
2024-10-26 21:38:15 UTC
I don't have a second monitor connected at the moment, but with a single screen I can see performance issues while SteamVR is running as well. Seems to be mostly, but not exclusively when I move the cursor. I can also reproduce this slowdown consistently. I currently have 1 monitor connected. It can do 144Hz, but I set it to 60Hz in systemsettings. The desktop runs at 60 FPS normally. I also have a Valve Index connected. Once I start VR (regardless of whether monado acquires the display lease via wayland or xlib), and box highlight the desktop to force repainting, the desktop FPS varies wildly anywhere between 30 and 60 FPS. I have the "Show FPS" desktop effect enabled to verify this. While it is true that having multiple monitors all at high refresh rates makes the slowdown much, much worse, it would seem this issue is not strictly exclusive to high-refresh-rate monitors nor multiple monitors. I can also reproduce this issue regardless of which kernel I'm using; have tested with LTS (6.6.58-1) and stable (6.11.5.arch1-1) kernels. I do not see any significant or even measurable uptick in CPU nor GPU usage. I notice that when running the desktop session with X11 instead, no slowdown occurs. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Arch Linux KDE Plasma Version: 6.2.2-1 KDE Frameworks Version: 6.7.0-1 Qt Version: 6.8.0-1 Wayland desktop, with xwayland also running GPU: AMD 5700 XTX, amdgpu driver Created attachment 175383 [details]
Bisect log performed on 2024-10-30T18:00:00-05:00
AFAICT this is a regression in behavior between KWin v6.2.1.1 and v6.2.2.
I added a bisect log.
first bad commit: [b7dbb2845bfe454efe75be8f7f1b1631f50be174] backends/drm: leave all outputs disabled by default, including VR headsets
This issue is still present in kwin 6.2.3. *** Bug 496011 has been marked as a duplicate of this bug. *** A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/6756 MR 6756 fixes the issue on my end (Monado, Valve Index, single monitor, amdgpu) Git commit f4d24cce43c59fc3fd57a34be8d43fe3033dd04f by Vlad Zahorodnii, on behalf of Xaver Hugl. Committed on 14/11/2024 at 12:03. Pushed by vladz into branch 'master'. backends/drm: fix DrmGpu::needsModeset check with leased outputs It just wrongly triggers modesets that will then (at least try to) ignore the leased-away resources anyways, and regress performance on the other displays. M +5 -3 src/backends/drm/drm_gpu.cpp https://invent.kde.org/plasma/kwin/-/commit/f4d24cce43c59fc3fd57a34be8d43fe3033dd04f Git commit 2d543f4a790b93c465caf2eb3504cb2915477924 by Xaver Hugl. Committed on 14/11/2024 at 12:46. Pushed by zamundaaa into branch 'Plasma/6.2'. backends/drm: fix DrmGpu::needsModeset check with leased outputs It just wrongly triggers modesets that will then (at least try to) ignore the leased-away resources anyways, and regress performance on the other displays. (cherry picked from commit f4d24cce43c59fc3fd57a34be8d43fe3033dd04f) Co-authored-by: Xaver Hugl <xaver.hugl@gmail.com> M +5 -3 src/backends/drm/drm_gpu.cpp https://invent.kde.org/plasma/kwin/-/commit/2d543f4a790b93c465caf2eb3504cb2915477924 |