Bug 495853

Summary: ~17% reduction in browser performance with extension enabled
Product: [Plasma] plasma-browser-integration Reporter: dofficialgman
Component: FirefoxAssignee: Kai Uwe Broulik <kde>
Status: REPORTED ---    
Severity: normal    
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description dofficialgman 2024-11-05 19:02:17 UTC 
SUMMARY
With only the plasma browser extension enabled, the browser performance as measured by the speedometer 3.0 benchmark is reduced by 17%. Within reasonable variance this can be observed across multiple of my tested hardware platforms. This reduced performance can be observed in many browser pages and is most easily quantifiable in the speedometer 3.0 benchmark.

STEPS TO REPRODUCE
1. install latest firefox
2. run speedometer 3 benchmark and note results
2. install plasma browser extension
3. run speedometer 3 benchmark and note results

OBSERVED RESULT
17% performance reduction

EXPECTED RESULT
no or minimal performance reduction such is the case with many other extensions

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu Noble 24.04
KDE Plasma Version: 5.27.11
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.13
Comment 1 Kai Uwe Broulik 2025-07-25 17:45:41 UTC 
Apart from a synthetic benchmark, is there any user-noticeable impact? I guess the mutation observer we install on the DOM to monitor for video players being added has quite some overhead.