Bug 411493

Summary:	kwrite memory usage when opening a rather big file
Product:	[Applications] kate	Reporter:	Isaac <isalgueiro>
Component:	kwrite	Assignee:	KWrite Developers <kwrite-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	anonkun, charpentier.franck, christoph, justin.zobel
Priority:	NOR
Version First Reported In:	19.08.0
Target Milestone:	---
Platform:	Neon
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	kwrite 20.08.2 CPU and memory usage

Description Isaac 2019-09-01 11:09:47 UTC

SUMMARY

After opening a 144MB file in kwrite and browsing its contents kwrite starts to consume 100% CPU and all the available memory. See #410129

STEPS TO REPRODUCE
1. Open a big file in kwrite
2. Press Ctrl End

OBSERVED RESULT

One of my CPU cores stays at 100% usage. Kwrite memory usage is very high, reaching ~8GB when I killed it. You can see KSysGuard attachements with this info in #410129


EXPECTED RESULT

Browse file contents.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.16.4
KDE Frameworks Version: 5.61.0
Qt Version: 5.12.3

ADDITIONAL INFORMATION

-

Comment 1 Dominik Haumann 2019-09-02 08:35:58 UTC

Does the shell script contain i) binary data, and / or ii) very long text lines?

Comment 2 Isaac 2019-09-02 08:46:38 UTC

Yes, it has binary data and very long lines

$ wc -L SoapUI-x64-5.5.0.sh
862 SoapUI-x64-5.5.0.sh

$ file SoapUI-x64-5.5.0.sh 
SoapUI-x64-5.5.0.sh: POSIX shell script executable (binary data)

Comment 3 Justin Zobel 2020-10-30 00:41:38 UTC

I can't replicate this on kwrite built from kate git master.

Isaac, can you please retest and confirm if this is still an issue.

Comment 4 Isaac 2020-10-31 09:35:02 UTC

Created attachment 132904 [details]
kwrite 20.08.2 CPU and memory usage

Comment 5 Isaac 2020-10-31 09:43:13 UTC

Just tried again (20.08.02) and this time CPU only spiked when scrolling through the file. IMO memory usage is still huge as you can see in the attached screenshot: that ~4GB step was the memory used by kwrite.

Overall responsiveness is way better than when I opened this issue, but still system felt a bit laggy until I closed kwrite.

I'm currently using:

Operating System: KDE neon 5.20
KDE Plasma Version: 5.20.2
KDE Frameworks Version: 5.75.0
Qt Version: 5.15.0
Kernel Version: 5.4.0-52-generic
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-8665U CPU @ 1.90GHz
Memory: 15,4 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 620

Comment 6 Justin Zobel 2020-11-01 01:17:24 UTC

Dominik does this extra info assist in diagnosing what might be causing this?

Comment 7 Christoph Feck 2020-11-09 23:50:53 UTC

Requested information was added with comment 5; changing status for inspection.

Comment 8 Christoph Cullmann 2020-12-15 20:32:46 UTC

*** Bug 413565 has been marked as a duplicate of this bug. ***

Comment 9 Christoph Cullmann 2020-12-15 22:01:08 UTC

*** Bug 421935 has been marked as a duplicate of this bug. ***

Comment 10 Christoph Cullmann 2023-08-03 19:59:36 UTC

We optimized some aspects, but large files still consume big chunks of memory.

If that should change, we need ideas and patches for that, otherwise we keep that as is, it is not unreasonable, we work well for the normal use cases.

https://kate-editor.org/post/2020/2020-07-18-contributing-via-gitlab-merge-requests/