Bug 409259 - Icons-only Task Manager hangs when switch desktops with pinned apps
Summary: Icons-only Task Manager hangs when switch desktops with pinned apps
Status: RESOLVED WORKSFORME
Alias: None
Product: plasmashell
Classification: Plasma
Component: Task Manager and Icons-Only Task Manager widgets (other bugs)
Version First Reported In: 5.23.5
Platform: Neon Linux
: NOR normal
Target Milestone: 1.0
Assignee: Eike Hein
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-06-27 16:55 UTC by Till Seifert
Modified: 2023-04-11 21:33 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


Attachments
Screen recording of workspace switching (2.16 MB, video/webm)
2019-06-29 13:49 UTC, Till Seifert
Details

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Description Till Seifert 2019-06-27 16:55:12 UTC
I'm running KDE NEON with Plasma 5.16.2, but this bug has been present unchanged in my setup since at least 5.15.

When i switch workspaces the plasmashell (desktop and all panels) freeze for about 1s–60s and use 100% of one CPU-core in that time. After that they become responsive again.
I see this only if a have (at the same time): 

a) the icon-only task-manager enabled
b) some Apps-icons pinned -> the more apps I pin, the longer the lang becomes. If i pin IntelliJ, if jumps especially, but every app increases it.

Grouping of icons or not doesd not affect it. Enabling "only icons from current workspace" does not affect it.


STEPS TO REPRODUCE
1. active one Icon-only Taskmanager plasmoid
2. configure it to only show icons from current workspace (this is to better see the lag)
3. open Firefox/Krwite/Konsole/Chrome each on one workspace and pin their icons in the Taskmanager
4. switch to workspaces
5. observe the icons. they update some time after the workspace was switched
6. Pin more Apps (open or not) to increase the delay



EXPECTED RESULT

The panel and taskmanager should update instantly after switching workspaces, which they do, if i pin no apps, even if many apps are open.


SOFTWARE/OS VERSIONS
Betriebssystem: KDE neon 5.16
KDE-Plasma-Version: 5.16.2
KDE-Frameworks-Version: 5.59.0
Qt-Version: 5.12.3
Kernel-Version: 5.0.5-050005-generic
Art des Betriebssystems: 64-bit
Prozessoren: 4 × AMD A8-6600K APU with Radeon(tm) HD Graphics
Speicher: 23,5 GiB Arbeitsspeicher
Comment 1 Till Seifert 2019-06-29 13:49:13 UTC
Created attachment 121218 [details]
Screen recording of workspace switching

Here is a screen recording. Even thou i did "unpin" all icons today i did not manage to get it back to completely snappy. But the increase in lag, after i pinned some apps, is visible.
Comment 2 Patrick Silva 2020-02-12 14:31:16 UTC
cannot reproduce here.

Operating System: Arch Linux 
KDE Plasma Version: 5.18.0
KDE Frameworks Version: 5.67.0
Qt Version: 5.14.1
Kernel Version: 5.5.2-arch2-2
OS Type: 64-bit
Processors: 2 × Intel® Celeron® CPU G1820 @ 2.70GHz
Memory: 7,7 GiB of RAM
Comment 3 Nate Graham 2020-02-12 16:24:25 UTC
Works for me too. Till, please re-open if it happens again in Plasma 5.18. Thanks!
Comment 4 Till Seifert 2020-02-18 13:08:59 UTC
Still happens the same way in 5.18.0, still lots of CPU usage and then the taskbar updates.

I tried to recreate it with pinned apps and without any pinned apps: 

* With all apps pinned (about 7) the lag was about 0.75s (this is a fresh session, it gets longer the longer i work)
* i *unpinned* all but one app: the lag was about 1.25s
* i unpinned the last app: the lag is now about 0.1s
Comment 5 galder 2022-01-30 16:04:54 UTC
Looks like an old issue. Setting it to needs more info.
Please try with a newer version(plasma 5.23.5) and if this is not an issue any more let us know.
Bugs placed into NEEDSINFO status will receive a reminder if the ticket:

    Is at least 15 days old
    Has not received any comment within 15 days

If a bug remains in NEEDSINFO for another 15 days with no comment, it will be closed as RESOLVED > WORKSFORME.
If a bug remains in NEEDSINFO with a comment provided within less than 15 days, no action will be taken (as it does not meet the above criteria).
Comment 6 Till Seifert 2022-02-05 12:55:07 UTC
> Please try with a newer version(plasma 5.23.5) and if this is not an issue
> any more let us know.

There is still lag and quite a CPU spike of the plasmashell-process, but even with some pinned Apps it maybe 100ms. 
So it is not really annoying any more.

But i have since switched to a faster CPU (2012 Athlon → 2020 Ryzen), so that skews it maybe.

So from a user perspective it would be ok to close the bug. But if devs want more info what might cause that, i would like to contribute to that.

Cheers!
Comment 7 Nate Graham 2022-02-07 16:11:50 UTC
That's good to hear. Still, there is clearly a performance bottleneck somewhere here. It should be instant. It is for me.
Comment 8 Nate Graham 2023-04-11 21:33:11 UTC
No further reports. Let's close it for now.