Bug 393548

Summary:	High cpu usage while scrolling a folder containing thousands of .jpg files
Product:	[Applications] dolphin	Reporter:	Patrick Silva <bugseforuns>
Component:	general	Assignee:	Dolphin Bug Assignee <dolphin-bugs-null>
Status:	CONFIRMED ---
Severity:	normal	CC:	elvis.angelaccio, mail
Priority:	NOR
Version First Reported In:	24.01.80
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Patrick Silva 2018-04-26 16:14:20 UTC

open ksysguard to observe cpu usage and enable "always on top" feature for its window
Use Dolphin to open a folder containing hundreds or thousands of jpg files (my test folders have 902 and 2140 files)
use your mouse wheel to scroll the folder content and observe Dolphin cpu usage

My cpu is Intel Celeron G1820 (2 cores, 2 threads), Dolphin cpu usage varies between 25% and 30% almost all the time if preview (thumbnails) feature is enabled. CPU usage varies more if preview is disabled (between 10 and 30%).

Comment 1 Julian Steinmann 2018-04-27 17:34:46 UTC

The preview function does indeed seem to be single-threaded. We should make it multi-threaded at some point.

Comment 2 Patrick Silva 2020-01-18 18:47:37 UTC

Dolphin 19.12.1 is affected.

Operating System: Arch Linux 
KDE Plasma Version: 5.17.90
KDE Frameworks Version: 5.66.0
Qt Version: 5.14.0

Comment 3 Patrick Silva 2023-11-30 15:16:29 UTC

With Dolphin 24.04 beta de cpu usage varies between 10% and 15% and the scrolling is slower than normal.

Operating System: Arch Linux 
KDE Plasma Version: 5.90.0
KDE Frameworks Version: 5.246.0
Qt Version: 6.6.1
Kernel Version: 6.6.3-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i5-4670K CPU @ 3.40GHz
Memory: 15,5 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 4600