Bug 141286 - Documents in Open Document format cause delay / lag when switching slides in "Normal" and Presentation Mode
Summary: Documents in Open Document format cause delay / lag when switching slides in ...
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Impress (show other bugs)
(earliest affected)
Hardware: All Linux (All)
: medium normal
Assignee: Not Assigned
Keywords: bibisected, bisected, perf, regression
Depends on:
Blocks: Performance
  Show dependency treegraph
Reported: 2021-03-27 14:21 UTC by sbub
Modified: 2023-10-10 05:36 UTC (History)
5 users (show)

See Also:
Crash report or crash signature:

Sample presentation that causes the delay / lag. (57.76 KB, application/octet-stream)
2021-03-27 14:23 UTC, sbub
Sample presentation as PPTX that does not cause the delay / lag. (47.51 KB, application/vnd.openxmlformats-officedocument.presentationml.presentation)
2021-03-27 14:24 UTC, sbub

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Description sbub 2021-03-27 14:21:49 UTC
I experience laggy performance in most recent Impress as observed here: https://ask.libreoffice.org/en/question/261988/libreoffice-calc-70-very-slow/

I can confirm that the delay is related to Open Document formats only.

The application seems to be a bit more responsive when changing through slides in the "Notes" view, but lacks massively in "Normal" and Presentation Mode (F5).
Files are local (SSD), no network involved running LibreOffice.


Steps to Reproduce:
1. Create a new Impress presentation
2. Add simple slides (no real content required)
3. Store as *.odp
4. Navigate through slides (e.g. via Page-Keys)

Actual Results:
delay/lag between slide changes around 2-3 seconds

Expected Results:
no delay between slide changes

Reproducible: Always

User Profile Reset: Yes

Additional Info:
Seems to be related to Open Document Format only as: saving the same presentation as *.pptx and then navigating through slides imposes no noticeable delay/lag.

Version: / LibreOffice Community
Build ID: 10(Build:2)
CPU threads: 4; OS: Linux 5.10; UI render: default; VCL: gtk3
Locale: de-DE (de_DE.UTF8); UI: de-DE
Calc: threaded
Comment 1 sbub 2021-03-27 14:23:56 UTC
Created attachment 170783 [details]
Sample presentation that causes the delay / lag.
Comment 2 sbub 2021-03-27 14:24:38 UTC
Created attachment 170784 [details]
Sample presentation as PPTX that does not cause the delay / lag.
Comment 3 Buovjaga 2021-03-27 16:19:43 UTC
The AskLibO link is a red herring. This started happening with version 7.1. Bibisected with linux-64-7.1 to https://git.libreoffice.org/core/commit/bf021c369f2306ee507da9bd3cc4cd10ac5d234c
tdf#135500: always use transparent and clear content vdev in impBufferDevice

As mentioned in the summary, the lag can be seen simply by switching the slides in the slide pane with PgUp/PgDn. However, you have to have the window maximised to really notice it.

I don't observe the lag on Windows.

Adding Cc: to Mike Kaganski
Comment 4 sbub 2021-03-27 17:37:26 UTC
Thank you for looking into the issue already.
I can confirm that it does not seem to happen on Windows (tested inside a VM).

Regarding maximized layout: I am running i3 window manager. I toggled between floating modes and different tiling scenarios, but did not see a real performance improvement. I guess it might still be "maximized" regarding the tiled window container.

What I don't understand looking at the bisected code is, why it does perform different when saved in PPTX format.

Comment 5 QA Administrators 2023-03-28 03:20:32 UTC Comment hidden (obsolete)
Comment 6 Timur 2023-10-09 18:43:22 UTC
Delay is not exact science, so we may experience it differently. 
I see some delay in LO 7.3 and 7.4 but not in 7.5 or 24.2. So I close. 
Should someone test it otherwise, please explain.
Comment 7 Buovjaga 2023-10-10 05:36:12 UTC
I don't notice any lag anymore

Arch Linux 64-bit, X11
Version: (X86_64) / LibreOffice Community
Build ID: 60(Build:1)
CPU threads: 8; OS: Linux 6.5; UI render: default; VCL: kf5 (cairo+xcb)
Locale: fi-FI (fi_FI.UTF-8); UI: en-US
Calc: threaded