Bug 416044 - Increased Energy Consumption of kwin wayland with active Screen Lock
Summary: Increased Energy Consumption of kwin wayland with active Screen Lock
Status: RESOLVED WORKSFORME
Alias: None
Product: kwin
Classification: Plasma
Component: wayland-generic (other bugs)
Version First Reported In: 5.17.5
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-01-09 13:19 UTC by Rainer Finke
Modified: 2022-02-18 04:37 UTC (History)
2 users (show)

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Description Rainer Finke 2020-01-09 13:19:39 UTC
I measured today the energy consumption on a AMD APU and experienced an increased energy consumption of kwin during an active screen lock. In my case the system consumed idle on the desktop 11 Watt (Wayland), but as soon as the lock screen kicks in, the system consumes continuously 13,5 Watt. Even if the screen is turned off, the energy consumption is with 12,5 Watt still higher than on an idle desktop.

If I open htop with ssh and look at the CPU% of kwin_wayland, it is on the desktop more or less idle (mostly at 0%), but with the lock screen it is at 5% and with the monitor turned off at 2%.

STEPS TO REPRODUCE
1. Open Plasma (Wayland)
2. Wait until the screen is locked

OBSERVED RESULT
- Increased energy consumption

EXPECTED RESULT
- Same or less energy consumption

Operating System: Arch Linux 
KDE Plasma Version: 5.17.5
KDE Frameworks Version: 5.65.0
Qt Version: 5.14.0
Kernel Version: 5.4.8-arch1-1
OS Type: 64-bit
CPU: AMD Ryzen 3 2200G
Comment 1 David Edmundson 2020-01-09 13:23:48 UTC
Is the mouse cursor flickering slightly?
Comment 2 Rainer Finke 2020-01-09 16:46:14 UTC
There is no mouse flickering. To verify, I've removed all USB devices, but there was no major difference on the lock screen regarding power consumption.
Comment 3 Christoph Feck 2020-01-20 12:01:52 UTC
Information was added with comment 2; changing status for inspection.
Comment 4 David Redondo 2022-01-19 15:19:34 UTC
There were rendering improvements in kwin, do you still see this?
Comment 5 Bug Janitor Service 2022-02-03 04:37:58 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 6 Bug Janitor Service 2022-02-18 04:37:09 UTC
This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!