VoxeLibre FPS Tanking Shortly After Starting Game

[Tech21101]

Hello all,

I've recently ran into an issue with VoxeLibre where, shortly after starting the game, probably a couple of minutes in, the FPS just tanks to uncomfortable levels. The computer I am running it on should have zero issues, especially considering it runs without much issue on my laptop, which is an old Thinkpad T460. I copied the world that is having this issue from that laptop, which runs Arch. The desktop runs Mint. I also loaded the few mods I have for the world onto the desktop. Switching to another world that was generated on the desktop, it seems to not have the same issue. That world does not have mods at all.

When I start the world, it runs perfectly smooth, but it eventually degrades to visibly choppy levels that makes it difficult to stand. Not sure what the FPS actually is, but it's not something I can just get over and play through.

Desktop Specs:

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OS: Linux Mint 22.2 x86_64 
Kernel: 6.14.0-35-generic
Packages: 2504 (dpkg), 17 (flatpak) 
Shell: bash 5.2.21 
Resolution: 1080x1920, 2560x1440 
DE: Cinnamon 6.4.8 
WM: Mutter (Muffin)
Terminal: flatpak-session 
CPU: AMD Ryzen 7 3700X (16) @ 3.600GHz 
GPU: NVIDIA GeForce RTX 3070 
Memory: 7223MiB / 32020MiB 

Mods:

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Animalia
Creatura
Simple Woodcutter
Unified Inventory

Thanks for any help in advance.

[sfan5]

Which version of Luanti are you using?
What are your engine settings (especially graphical effects)? Did you try changing them?
Did you try disabling the mods you have?

Not sure what the FPS actually is, but it's not something I can just get over and play through.

You can see the exact FPS by pressing F5.
Pressing F6 will also cycle through the pages of the internal profiler. Screenshots of them would be helpful.

[Astrobe]

With debug privilege, F5 also let one access to "wireframe" and collision box display, which let you see mobs through walls. I experienced heavy FPS drops a couple of times because of massive spawning of mobs underground. It's probably not the case here, because those drops are typically local and directional (looking away restores FPS), but who knows.

[Tech21101]

Which version of Luanti are you using?
What are your engine settings (especially graphical effects)? Did you try changing them?
Did you try disabling the mods you have?

Version 5.14.0, Same as what's running on my laptop.

Graphics settings/effects are basically default, I did have waving trees/plants/water on, but I disabled them and it does the same thing. I did have more settings on before, but I disabled them as well thinking the FPS issue was caused by that.

I disabled my mods before as well, no difference in behavior.

You can see the exact FPS by pressing F5.
Pressing F6 will also cycle through the pages of the internal profiler. Screenshots of them would be helpful.

I don't know why I didn't think to use the F5 display for that. In any case, the lowest FPS I experienced was 12. Keep in mind, when the world first starts, it's 144, and it gradually gets lower and lower.

As for the profiler screenshots, I've taken them at world start and when the FPS is lowest:
High FPS, P1:

P2:

P3:


Low FPS, P1

P2:

P3:

With debug privilege, F5 also let one access to "wireframe" and collision box display, which let you see mobs through walls. I experienced heavy FPS drops a couple of times because of massive spawning of mobs underground. It's probably not the case here, because those drops are typically local and directional (looking away restores FPS), but who knows.

There were actually a lot of mobs around me, but that's also true at world start, and looking away didn't improve FPS at all.

[Astrobe]

Another cause of FPS drops (recoverable, though) is the parameter: "Mapblock mesh generation delay" in Advanced settings (tick "advanced settings" and search for "mesh"). Set it to 1 to 5. With the default value (0), when walking long enough, FPS progressively drops on my old rig (i3, GTX).

[Tech21101]

Another cause of FPS drops (recoverable, though) is the parameter: "Mapblock mesh generation delay" in Advanced settings (tick "advanced settings" and search for "mesh"). Set it to 1 to 5. With the default value (0), when walking long enough, FPS progressively drops on my old rig (i3, GTX).

It exhibits the same behavior after setting the value to 5, unfortunately. I suppose it isn't quite as fast to occur as I thought it was, it does take some time to drop all the way down to 15 FPS.

[sfan5]

As for the profiler screenshots, I've taken them at world start and when the FPS is lowest:
[...]

From the FPS information alone I can tell you that it's not a rendering issue, since 7ms rendering time should get you about 142 FPS.

What is very suspicious is that the profiler is saying that the client is doing so many collision calculations.
That would be ~300ms of every second, or more than 13000 calculations per object (there are just 100).

Did you try the wireframe advice to see if anything unexpected is in the map? Note that you need to /grantme debug for this.

[Astrobe]

Does it include particle collisions as well ?

[sfan5]

Yes. On the client collision detection can run for: particles, entities and the local physics.

[Tech21101]

[...]

Did you try the wireframe advice to see if anything unexpected is in the map? Note that you need to /grantme debug for this.

Nothing particularly strange, just a regular amount of entities.



I suppose I should also look at this on my laptop as well, considering it doesn't have these issues.

[sfan5]

I think the most realistic way anyone can debug this issue would be if you were to upload a copy of your world.
No promise that I have time to look at it soon, however.