Bug 121860 - System slows down (freezes) while marking/selecting a lot of single cells by Ctrl+Left Mouse Click
Summary: System slows down (freezes) while marking/selecting a lot of single cells by ...
Status: NEW
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Calc (show other bugs)
(earliest affected)
4.4 all versions
Hardware: x86-64 (AMD64) Linux (All)
: medium major
Assignee: Not Assigned
Keywords: bibisectRequest, haveBacktrace, perf, regression
: 114767 (view as bug list)
Depends on:
Blocks: CPU-AT-100%
  Show dependency treegraph
Reported: 2018-12-02 12:02 UTC by einsachtzehn
Modified: 2019-03-05 16:39 UTC (History)
6 users (show)

See Also:
Crash report or crash signature:

Video that shows described behavior and output of top command (1.04 MB, video/mp4)
2018-12-17 19:18 UTC, einsachtzehn
Callgrind output from master (1.21 MB, application/x-xz)
2019-01-25 18:30 UTC, Buovjaga

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Description einsachtzehn 2018-12-02 12:02:30 UTC
After 10-15 cells are selected by STRG+Mouse Click there is a significant loss of speed in marking others. The more you choose the longer one have to wait until cells selection is shown.
Comment 1 einsachtzehn 2018-12-02 13:09:32 UTC
Steps to reproduce:
1 Open a calc sheet
2 press and hold STRG and mark several cells or ranges (between 10-15)

Actual Results:
Calc needs more time to show cells selection the more you try to mark

Expected Results:
Stable performance while marking cells

Reproducible: Always
Comment 2 Durgapriyanka 2018-12-02 16:44:16 UTC
Thank you for reporting the bug. I cannot reproduce the bug in

Build ID: 0c292870b25a325b5ed35f6b45599d2ea4458e77
CPU threads: 2; OS: Windows 6.1; UI render: default; 
Locale: en-US (en_US); Calc: group
Comment 3 einsachtzehn 2018-12-02 20:39:13 UTC
Made some additional tests related to this.
After application restart the behavior occurs between 20-30 cells that are marked
Second try with same sheet still open between 10-20 cells
Seems that the more often you try the earlier the application slows down. 
CPU usage goes up to 100 percent while marking.
Comment 4 einsachtzehn 2018-12-08 22:53:16 UTC
Another notice:
Bug seems to be in connection with marking of several SINGLE cells only.

Bug does not come up if one or more ranges are marked at first that contain a lot of cells before single cells are additionally(!) marked.
Then a huge number of single cells can be marked without any system slow-down.

Bug does come up if a lot of single cells are marked.
Comment 5 einsachtzehn 2018-12-17 19:18:29 UTC
Created attachment 147633 [details]
Video that shows described behavior and output of top command
Comment 6 Roman Kuznetsov 2018-12-21 21:27:46 UTC
confirm in

Build ID: 0412ee99e862f384c1106d0841a950c4cfaa9df1
CPU threads: 4; OS: Linux 4.13; UI render: default; VCL: gtk3; 
Locale: ru-RU (ru_RU.UTF-8); UI-Language: en-US
Calc: threaded
Comment 7 Xisco Faulí 2018-12-26 15:52:28 UTC
Reproduced in

Build ID: c15927f20d4727c3b8de68497b6949e72f9e6e9e

but not in

Version (Build ID: efca6f15609322f62a35619619a6d5fe5c9bd5a)
Comment 8 Buovjaga 2019-01-25 14:26:37 UTC
I can repro with master, but cannot repro with Linux bibisect repos 43, 44, 50max. Weird!!
Comment 9 Buovjaga 2019-01-25 18:30:15 UTC
Created attachment 148664 [details]
Callgrind output from master

Continued clicking until slowness was noticeable.

Arch Linux 64-bit
Build ID: bb30e9e591d5f9f913b3cd8fbaa3c5e412b509bd
CPU threads: 8; OS: Linux 4.20; UI render: default; VCL: gtk3; 
Locale: fi-FI (fi_FI.UTF-8); UI-Language: en-US
Calc: threaded
Built on 23 January 2019
Comment 10 Buovjaga 2019-02-18 12:03:45 UTC
*** Bug 114767 has been marked as a duplicate of this bug. ***
Comment 11 Martin Pietsch 2019-03-05 13:59:26 UTC
I was able to reproduce this behaviour with version on Ubuntu 16.04.6 LTS and ArchLinux. I also found out that this behaviour occurs with KDE in combination with the X11 composer. If you use KDE with the wayland composer, LibreOffice will run as usual.