Low update FPS when many notes are on screen in mania

[longnguyen2004]

Type

Performance

Bug description

I was playing a storyboard map, which has the SV multiplier set to 0.01x to prevent turning off the storyboard. However, there are huge lag throughout the map. So I turned off the storyboard to see if it persists, which it did, so it's not due to the storyboard.

Also, this is not related to SV changes during the map, but note density in general. You can take any maps, reduce the scroll speed to minimum, and it'd exhibit the same problem (screenshot below).

Screenshots or videos

Version

2023.924.1

Logs

probably not required

[peppy]

Please provide a link to the beatmap.

[longnguyen2004]

https://osu.ppy.sh/beatmapsets/1248233#mania/2594303 - loved map with 0.01x SV multiplier throughout (turn off storyboard to confirm it's not the storyboard)

But like I said, you can pick any maps, set scroll speed to 1, and the same perf degradation will occur.

[longnguyen2004]

Map: https://osu.ppy.sh/beatmapsets/533893#mania/1131026, scroll speed set to minimum to exaggerate the issue

Argon/Argon Pro

Triangles

Classic

R Skin v3.1

[peppy]

Does the performance improve when you pause the game? The majority of the overhead looks to be update bound, so it's likely related to animations / movement.

[longnguyen2004]

Yes, if I pause then the performance issue goes away.

On an unrelated note, I also observed that there's a momentary stutter on the update thread for every note hit, which you can also see on the 2nd screenshot (very spiky frametime graph for Update), and it gets worse the longer the map goes on. Should I report it here as well or as another issue?

[peppy]

It's fine to track that here. I'll look into both.

[longnguyen2004]

Turns out it's a problem with the UR display, which recalculates the UR by iterating through every HitEvents since the start of gameplay, at least from what I can tell, thus the performance gets worse the more hit events there are.

While it's not mania-specific, I can make an issue if you want something to keep track of. The other issue related to note density remains however

[peppy]

In that case please make a separate issue to track, thanks!