| Summary: | On laptop with Radeon 780M GPU, 6.1.4 causes Triple Buffering to produce graphical corruption in XWayland apps and lag in all apps | ||
|---|---|---|---|
| Product: | [Plasma] kwin | Reporter: | Nate Graham <nate> |
| Component: | performance | Assignee: | KWin default assignee <kwin-bugs-null> |
| Status: | REPORTED --- | ||
| Severity: | major | CC: | fabian+kdebugs, micraft.b, xaver.hugl |
| Priority: | NOR | Keywords: | regression |
| Version: | 6.1.4 | ||
| Target Milestone: | --- | ||
| Platform: | Other | ||
| OS: | Linux | ||
| See Also: | https://bugs.kde.org/show_bug.cgi?id=493073 | ||
| Latest Commit: | Version Fixed In: | ||
| Sentry Crash Report: | |||
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Description
Nate Graham
2024-08-28 14:04:56 UTC
I am observing similar problems with stutter. To me, it looks like this problem is caused solely by the high VRAM consumption, and (possibly) the resulting usage of GTT memory: With multiple monitors connected to my 7840U Laptop, I am observing the stutter regardless of kwins triple buffering settings. Connecting multiple external monitors causes VRAM usage to pretty much always get beyond the 512 MiB of VRAM the firmware of my Laptop has allocated, even with only a few open applications. I can work around this issue by enabling a gaming option in the UEFI of the laptop, so 4 GiB of VRAM are reserved. In this case, the stutter is not observable, even with triple buffering enabled. If disabling triple buffering doesn't help for your issue, it sounds like a different one, though possibly related. Can you open a new bug report about it? Thanks! I would have, but I do think that these issues are very closely related, if not the same. I don't think that disabling triple buffering fixed the stuttering for you. I have the feeling that the associated reduced memory consumption fixed it. For me, disabling triple buffering is not suffucient to reduce VRAM consumption to less than 100%, at least with multiple external monitors connected. If your device has an option to increase the dedicated VRAM allocation, it might be worth checking if that fixes the stuttering for you as well. If it does not, I will create a new bug report. Disabling triple buffering did reduce VRAM usage, but only by a small amount. Most of the time it was still listed as over 100% on login. GTT was low regardless of whether it's on or off. I talked to a KWin developer who said that the VRAM usage reported by `radeontop` is not really trustworthy since it has a weird way of measuring VRAM usage. Apparently it always shows up as close to 100% due to the way it counts shared memory allocations. I'll look in the device's UEFI to see if it has an option for this, but I'm not hopeful on that front. It's not a fancy gaming laptop, just an HP Pavilion Plus 14. *** Bug 493073 has been marked as a duplicate of this bug. *** (In reply to Fabian Blaese from comment #1) > I am observing similar problems with stutter. > > To me, it looks like this problem is caused solely by the high VRAM > consumption, and (possibly) the resulting usage of GTT memory: With multiple > monitors connected to my 7840U Laptop, I am observing the stutter regardless > of kwins triple buffering settings. Connecting multiple external monitors > causes VRAM usage to pretty much always get beyond the 512 MiB of VRAM the > firmware of my Laptop has allocated, even with only a few open applications. > > I can work around this issue by enabling a gaming option in the UEFI of the > laptop, so 4 GiB of VRAM are reserved. In this case, the stutter is not > observable, even with triple buffering enabled. The amount of memory you see as "VRAM" is not what the GPU can use, it's a very small amount reserved for the GPU. Using more than it should never have a noticeable performance impact - that "gaming" option is mostly a workaround for buggy games that assume they always run on a dedicated GPU and don't launch unless they have x amount of "VRAM". Most likely the "gaming" option changes more than the amount of reserved memory. |