Bug 388258

Summary: kscreenlocker_greet consumes 30% cpu in VNC-server
Product: [Unmaintained] kscreenlocker Reporter: slartibart70
Component: generalAssignee: Plasma Bugs List <plasma-bugs-null>
Status: RESOLVED WORKSFORME    
Severity: normal CC: aspotashev, bshah, kde, mgraesslin, plasma-bugs-null, rdieter
Priority: NOR Keywords: triaged
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Fedora RPMs   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description slartibart70 2017-12-26 21:33:43 UTC
fedora27,testing-repos,
plasma 5.11.4, k-frameworks 5.41

I have plasma5 running in an vncserver-process which is most of the time, idle.
After using it for some while with vncviewer and killing the vncviewer window, the kscreenlocker_greet process consumes up to 30% cpu time (on one cpu core) - which is waaay too much!

The screenlocker is only displaying a static image, no slideshow
Comment 1 David Edmundson 2017-12-28 23:47:22 UTC
Please state your Qt version.

Also can you run the attached case with qmlscene from comment #1 here.
https://bugs.kde.org/show_bug.cgi?id=386846

and tell me if you get an error there.

finally can you run kscreenlocker_greet with both QSG_RENDER_LOOP=basic and =threaded
Comment 2 slartibart70 2017-12-29 21:41:21 UTC
qt is still on 5.9.2
according to https://bugs.kde.org/show_bug.cgi?id=386846, errors appear also with qt 5.10.5.
My peculiar problem can be worked around by killing the vnc session and restarting the vnc server. Then (without logging in at all) the cpu consumption is about 10% (on a 16core machine), so this is ... quite ok for me at the moment...
Comment 3 Christoph Feck 2018-01-10 18:54:08 UTC
The reference to 5.10.5 was for the Plasma version. Qt only released version 5.10.0, and you would need to test this version.
Comment 4 Andrew Crouthamel 2018-09-28 03:35:12 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 set the bug status 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 5 Andrew Crouthamel 2018-10-29 02:14:38 UTC
Dear Bug Submitter,

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!
Comment 6 Alexander Potashev 2018-11-20 03:30:38 UTC
I have a similar problem on a regular X server without VNC. kscreenlocker_greet's CPU load is somewhere between 15% and 50% most of the time (these are percentages of 1 hyper-threaded core capability).

OS: Fedora 28
Plasma 5.13.5
Qt 5.11.1
KF 5.52.0
Comment 7 Alexander Potashev 2018-12-25 09:57:47 UTC
(In reply to Alexander Potashev from comment #6)
> I have a similar problem on a regular X server without VNC.
> kscreenlocker_greet's CPU load is somewhere between 15% and 50% most of the
> time (these are percentages of 1 hyper-threaded core capability).
> 
> OS: Fedora 28
> Plasma 5.13.5
> Qt 5.11.1
> KF 5.52.0

Shall I create a new bug report for my case?
Comment 8 David Edmundson 2018-12-25 10:13:51 UTC
Search bugzilla first, there's a thread where switching to the software renderer fixes it.
Comment 9 Alexander Potashev 2018-12-25 11:09:00 UTC
You probably meant https://bugs.kde.org/show_bug.cgi?id=347772

Well, can't reproduce at the moment, will report next time I detect high CPU load. Thanks!
Comment 10 David Edmundson 2018-12-25 23:25:37 UTC
That's the one. Report back if it helps or not, I might try and automate the detection.