Bug 133849

Summary:	Automatic spell check in calc with many misspelled words causes high CPU load scrolling and text movement
Product:	LibreOffice	Reporter:	Telesto <telesto>
Component:	Calc	Assignee:	Not Assigned <libreoffice-bugs>
Status:	RESOLVED INSUFFICIENTDATA
Severity:	normal	CC:	buzea.bogdan, ilmari.lauhakangas, vsfoote
Priority:	medium
Version:	5.3.0.3 release
Hardware:	All
OS:	All
Whiteboard:
Crash report or crash signature:		Regression By:
Bug Depends on:
Bug Blocks:	96000, 146014

Description Telesto 2020-06-10 09:02:25 UTC

Description:
The spell checker in Calc only checks the on screen part of wrong spelled words. In principle no issue with that. However if you start scrolling, the spell checker 'restarts' checking everything on screen. So also the already checked part. Nothing is cached..

So spell checker is doing same stuff multiple times.. At the same time causes the restart the spell checker repaints of the red underlining.. which means shaping text over and over. And shaping text isn't cheap anymore (since Harfbuzz). 

Which - both together - creates an massive CPU load while scrolling moving text 

Steps to Reproduce:
1. Open the attached file
2. Automatic spell check enabled. Scroll up down & monitor CPU usage

Actual Results:
15-25% depending on scroll speed etc

Expected Results:
Can be improved


Reproducible: Always


User Profile Reset: No



Additional Info:
Version: 7.1.0.0.alpha0+ (x64)
Build ID: 59939d2490726336546c7ad05082d23031074e12
CPU threads: 4; OS: Windows 6.3 Build 9600; UI render: default; VCL: win
Locale: nl-NL (nl_NL); UI: en-US
Calc: CL

Comment 1 Buovjaga 2021-05-07 15:34:35 UTC

(In reply to Telesto from comment #0)
> Steps to Reproduce:
> 1. Open the attached file

Please attach an example document.
Set to NEEDINFO.
Change back to UNCONFIRMED after you have provided the document.

Comment 2 QA Administrators 2021-11-04 04:10:14 UTC Comment hidden (obsolete)

Dear Telesto,

This bug has been in NEEDINFO status with no change for at least
6 months. Please provide the requested information as soon as
possible and mark the bug as UNCONFIRMED. Due to regular bug
tracker maintenance, if the bug is still in NEEDINFO status with
no change in 30 days the QA team will close the bug as INSUFFICIENTDATA
due to lack of needed information.

For more information about our NEEDINFO policy please read the
wiki located here:
https://wiki.documentfoundation.org/QA/Bugzilla/Fields/Status/NEEDINFO

If you have already provided the requested information, please
mark the bug as UNCONFIRMED so that the QA team knows that the
bug is ready to be confirmed.
 
Thank you for helping us make LibreOffice even better for everyone!

Warm Regards,
QA Team

MassPing-NeedInfo-Ping

Comment 3 QA Administrators 2022-01-02 03:56:05 UTC

Dear Telesto,

Please read this message in its entirety before proceeding.

Your bug report is being closed as INSUFFICIENTDATA due to inactivity and
a lack of information which is needed in order to accurately
reproduce and confirm the problem. We encourage you to retest
your bug against the latest release. If the issue is still
present in the latest stable release, we need the following
information (please ignore any that you've already provided):

a) Provide details of your system including your operating
   system and the latest version of LibreOffice that you have
   confirmed the bug to be present

b) Provide easy to reproduce steps – the simpler the better

c) Provide any test case(s) which will help us confirm the problem

d) Provide screenshots of the problem if you think it might help

e) Read all comments and provide any requested information

Once all of this is done, please set the bug back to UNCONFIRMED
and we will attempt to reproduce the issue. Please do not:

a) respond via email 

b) update the version field in the bug or any of the other details
   on the top section of our bug tracker

Warm Regards,
QA Team

MassPing-NeedInfo-FollowUp