Bug 504525

Summary:	Switching view mode in Processes page is slow, especially on older hardware.
Product:	[Applications] plasma-systemmonitor	Reporter:	Tamás Králl <tamaskrall42>
Component:	general	Assignee:	KSysGuard Developers <ksysguard-bugs>
Status:	CONFIRMED ---
Severity:	minor	CC:	ahiemstra, aspotashev, kde, nate, plasma-bugs-null
Priority:	NOR	Keywords:	efficiency-and-performance
Version First Reported In:	6.3.90
Target Milestone:	---
Platform:	Neon
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	Video showing the load times of Processes and view switching

Description Tamás Králl 2025-05-19 13:56:43 UTC

SUMMARY
When switching between List and Tree view mode on the Processes page, the app stutters for a while. Since it's just reordering the elements it feels like it's taking too long to do this change.

STEPS TO REPRODUCE
1. Go to Processes page
2. Change view mode to Tree
3. Change view mode to List

OBSERVED RESULT
Changing the view mode takes about 2 seconds.

EXPECTED RESULT
Changing the view mode is immediate or doesn't take noticably long. 

SOFTWARE/OS VERSIONS
System Monitor: 6.3.90
KDE neon Unstable Edition (Wayland)
KDE Frameworks: 6.15.0
Qt: Using 6.9.0 and built against 6.9.0
Build ABI: x86_64-little_endian-lp64
Kernel: linux 6.11.0-25-generic

Comment 1 Nate Graham 2025-05-19 18:10:35 UTC

Hmm, it's instant for me.

What kind of hardware are you using? Can you paste the output of `kinfo | tail -n 3`?

Comment 2 Tamás Králl 2025-05-19 19:58:10 UTC

Here it is:
ERROR:             VkInstanceCreateInfo::pApplicationInfo::apiVersion has value of 0 which is not permitted. If apiVersion is not 0, then it must be greater than or equal to the value of VK_API_VERSION_1_0 [VUID-VkApplicationInfo-apiVersion]
MESA-INTEL: warning: Haswell Vulkan support is incomplete
Processors: 4 × Intel® Core™ i5-4210U CPU @ 1.70GHz
Memory: 8 GiB of RAM (7.7 GiB usable)
Graphics Processor: Intel® HD Graphics 4400

Comment 3 Nate Graham 2025-05-19 20:38:21 UTC

Ok, so it seems this is some hind of hardware incompatibility where we're using a library that's trying to do Vulkan things, but your hardware doesn't support Vulkan?

Comment 4 Tamás Králl 2025-05-19 21:01:38 UTC

I'm not sure the Vulkan support error is related to the slow view switching, but it might be. It may just be that the CPU lacks performance and the view switching isn't hardware accelerated.

Someone with access to a Vulkan-supported machine running the latest Plasma could test this by running it on bare metal and comparing it with a VM somehow limiting Vulkan usage (if this is even possible).

Comment 5 David Redondo 2025-05-20 09:21:59 UTC

We wouldn't be using Vulkan anyway.

Comment 6 David Redondo 2025-05-20 09:26:02 UTC

Intel Haswell is from 2013 and 1.7GHz is not a lot nowadays.

> . Since it's just reordering the elements it feels like it's taking too long to do this change.

Unfortunately this is not what is happening the whole model behind changes from a list to a tree and all items are recreated. Do you feel it takes longer than the initial load? It certainly also stutters on my system but I fear that could be all in upstream treeview

Comment 7 Tamás Králl 2025-05-20 16:15:29 UTC

Created attachment 181578 [details]
Video showing the load times of Processes and view switching