Bug 404604

Summary:	Weak GPUs can cause frame drops or high CPU usage when using hardware rendering
Product:	[Frameworks and Libraries] frameworks-qqc2-desktop-style	Reporter:	Patrick Silva <bugseforuns>
Component:	general	Assignee:	Marco Martin <notmart>
Status:	CONFIRMED ---
Severity:	normal	CC:	aleixpol, grouchomarx.fr, kde, nate, sepamou
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Patrick Silva 2019-02-20 16:04:27 UTC

SUMMARY
cursor movements and plasma animations lag weirdly on my system while Discover app store is running.
I enabled Show FPS effect in Desktop Effects kcm, it indicates that the framerate decreases to 15 while Discover is running and I move cursor. When Discover is not running, framerate is 60fps.


SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 5.15.1
KDE Frameworks Version: 5.55.0
Qt Version: 5.12.1
Kernel Version: 4.20.10-arch1-1-ARCH

Comment 1 Aleix Pol 2019-02-22 00:35:17 UTC

Can you try with another kirigami app? like the kirigami gallery, for example.

Comment 2 Patrick Silva 2019-02-22 00:56:48 UTC

I can't reproduce the problem using kirigami gallery.
I have just noticed that framerate only decreases while Discover window is maximized and not minimized.

Comment 3 Patrick Silva 2019-04-23 13:56:48 UTC

This problem persists.
Now it only occurs while I move cursor on maximized Discover window.
Framerate is 60 fps if Discover is maximized and focused but cursor is stopped.

Operating System: Arch Linux 
KDE Plasma Version: 5.15.4
KDE Frameworks Version: 5.57.0
Qt Version: 5.13.0 beta2
Kernel Version: 5.0.9-arch1-1-ARCH

Comment 4 Patrick Silva 2019-06-16 17:29:27 UTC

This bug is still happening when I move cursor on the lists of installed or featured apps, no matter if Discover window is maximized or not.
No problem when I move the cursor on the side bar or on "About" or "Sources" pages.

Comment 5 Patrick Silva 2019-07-14 17:06:26 UTC

*** Bug 409035 has been marked as a duplicate of this bug. ***

Comment 6 Patrick Silva 2019-07-14 17:08:41 UTC

As we can read in bug 409035 marked as duplicate, system settings is also affected. What is the correct product for this bug?

Comment 7 grouchomarx.fr 2019-12-29 14:08:55 UTC

If I launch intel_gpu_top on my ironlake GPU, the Render/3D/0 row reaches 100% when I move my mouse around to quickly trigger these fade-in fade-out animations when these apps (discover and system settings) are maximized on a FHD monitor.

If I trigger what looks like the same kind of animations in dolphin, it stays under 3%.

Comment 8 grouchomarx.fr 2020-02-26 20:30:36 UTC

It seems that my bug 409035 concerns QtQuick apps and the fact that they are using Opengl to render everything. They make my Ironlake GPU hit 100% very easily.
If I force the software backend, the desktop is fluid again.

It is very likely that my GPU is too weak. But it may also come from the apps, QtQuick, or the driver. I am not sure how to debug this.

In the meantime, I am using QT_QUICK_BACKEND=software as a workaround.

Comment 9 Nate Graham 2021-01-26 21:33:47 UTC

Yeah this is a general problem with really weak GPUs. :/

Comment 10 Nate Graham 2021-03-19 20:03:24 UTC

*** Bug 423935 has been marked as a duplicate of this bug. ***