Eats up all CPU while mixer is open and instrument change is expanded
Reported version
3.0
Type
Functional
Frequency
Few
Severity
S3 - Major
Reproducibility
Always
Status
active
Regression
Yes
Workaround
Yes
Project
Version: 3.0.2
If I use “Change Instrument” to e.g. split a vocal piece into Tutti - Soli - Tutti, then go to the mixer and click the arrow to expand them, MuseScore uses 100% CPU. As soon as I collapse them with the arrow button, CPU usage goes back down.
(And how do I change the label at the bottom? It says S.-normal for all three Sopranos, etc. for the other voices. In a larger piece with multiple instrument changes, this becomes unmanageable.)
Comments
Might be related to #289082: High CPU load with Mixer and opened channels and a return of #278897: High CPU load while the mixer is open after the mixer got changed in 3.0.1
Yes, I think #289082 is a duplicate of this one.
Also if I remember it correctly it is related to #278897: High CPU load while the mixer is open which got fixed by https://github.com/musescore/MuseScore/pull/4245.
A similar approach would fix this issue too but there were some issues with proper style updating (e.g. dark/light theme) in case of switching it while the mixer is open. This is certainly not a critical issue but it would be good to keep it working while fixing this issue.
Yes, that was my suspicion
Oh, didn't read the second part of the Jojo's comment. It is actually not a returning of that issue but just the same issue for another Mixer widget as these widgets seem to implement style changes handling in a similar way.
Edit: now I missed one more comment before posting :)
As per https://musescore.org/de/node/288886#comment-918635 there might be more to it, seems all 3.x releases are affected, even 3.0.0, which should have the fix for #278897: High CPU load while the mixer is open
OS: openSUSE Leap 15.0, Arch.: x86_64, MuseScore version (64-bit): 3.3.0., revision: 4761df6
The problem persists.
More precisely: Uses a full CPU core.
Ergo 4-core CPU 25 percent CPU load.
On my Windoes 7 PC with 4 cores +HT, I see the load go to ~13%, but in task manager it doesn't show a single core maxing out, but 4 at about 25%, the other 4 being idle.
So the load percentage matches your's, but not the single core maxing out
In reply to On my Windoes 7 PR 4 cores … by Jojo-Schmitz
Then Windows just handles distributing the load better ☻
Came up again in https://musescore.org/de/node/313493
At https://youtu.be/d605ftD-_XA there's a video describing the behavoir