Bug 454462

Summary:	Editor is extremely laggy
Product:	[Applications] kdevelop	Reporter:	Aaron Williams <aaronw>
Component:	UI: general	Assignee:	kdevelop-bugs-null
Status:	RESOLVED WORKSFORME
Severity:	normal
Priority:	NOR
Version First Reported In:	5.8.220401
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Aaron Williams 2022-05-27 04:38:57 UTC

SUMMARY
While editing my C projects the editor is often extremely laggy, sometimes taking seconds to catch up.
This is running on a 12 core machine with 128GiB of RAM with all data on an nVME SSD.

STEPS TO REPRODUCE
1.  Open a moderately sized C project
2.  Edit C files
3.  Experience frequent lag in the editor

OBSERVED RESULT
I observe very noticeable lag frequently in the editor, perhaps related to the code completion. I have Clazy Levels 0 and 1 enabled. This is using the C custom script formatter using Clang Format.

EXPECTED RESULT
I expect the editor to respond quickly like previous releases

I am also wondering if this is related to the problem which causes KDevelop to hang when shutting down where a database appears to be getting corrupted.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION

Comment 1 Milian Wolff 2022-05-30 08:16:38 UTC

please use a profiler to investigate the sources of the lagging, ideally use something like hotspot with combined on-CPU and off-CPU profiling then concentrate on the main thread.

it's not laggy on my machine(s) which all have less RAM than you

Comment 2 Aaron Williams 2022-06-01 03:47:22 UTC

One thing I see is that it is constantly rescanning the project and I see several stuck kdevelop processes consuming 100% of the CPU. I think this may be related to another bug in KDevelop where it fails to shutdown and consumes 100% of the CPU. I am also experiencing that known bug. If I had to guess, it's due to the background scanner not shutting down properly. Every time the editor stutters it started another parsing episode.

Comment 3 Milian Wolff 2022-06-01 07:40:19 UTC

when a kdev instance is still running, you wouldn't be able to reopen the session. anyhow, easy to test - kill all kdevelop instances and start it fresh, does it still lag? if so, profile, instead of letting us guess at the faults.

Comment 4 Aaron Williams 2022-06-01 15:01:45 UTC

yes. It is still laggy with frequent reparsing with two more processes stuck at 100%

Comment 5 Bug Janitor Service 2022-06-16 04:35:32 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 2022-07-01 04:37:17 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!