Vulkan: GIProbe very slow on AMD RX480 and Linux

[pihdastudios]

Godot version:

43f89e7

OS/device including version:

Linux Mint 20.1
Kernel 5.8.0-48-generic #54~20.04.1-Ubuntu

AMDVLK 2021.Q2.1 and radv 20.2.6

AMD RX 480 8Gb
AMD Ryzen 7 3700X

Build Command
scons p=linuxbsd target=debug module_mono_enabled=no -j16 CXX=g++-10 CC=gcc-10

Issue description:

GIProbes on any mesh with or without light would create a performance issue.

Also selecting the mesh after setting it to disabled baking and baking GIProbe also creates a performance issue

Steps to reproduce:

1. Create a scene
2. Add mesh (Cube)
3. Set to baked Dynamic
4. Add GIProbe
5. Bake

And

1. Create a scene
2. Add mesh (Cube)
3. Add GIProbe
4. Bake (Everything is still fine by now)
5. Select Mesh

Minimal reproduction project:
giprobe-test.zip

[Calinou]

See also #36121, which is pretty old and may not be relevant with the current state of GIProbe.

@pihdastudios Can you define "very slow"? Is the slowless persistent or does it occur only when moving a node?

[pihdastudios]

@pihdastudios Can you define "very slow"? Is the slowless persistent or does it occur only when moving a node?

Near freezing and persistent, it slows down my entire desktop.
Godot still can receive inputs (clicking buttons, moving nodes) but you'd have to wait around 2 seconds.

It would dissapear if you cleared the GIProbe data

[pihdastudios]

This also happens on Windows 10 with AMD Adrenalin 21.3.2. So its probably a hardware thing.

[novemberist]

I can confirm this. I'm also on Linux and with an AMD GPU (RX 580). This issue has been present for me for at least a year now. I think this started around the time the DisplayServer changes/multiple windows support was introduced.

[Calinou]

VoxelGI in master is currently broken in my experience (it often makes everything black), unless you combine it with SDFGI at the same time.

Edit: I bisected this and found that GIProbe broke on commit 1f96ba5.

Minimal reproduction projects for testing VoxelGI: giprobe_old.zip (old mesh format) and giprobe_old2.zip (new mesh format). The VoxelGI node intentionally doesn't extend all the way through so you can see the difference with and without GI.
Note: On latest master, you will have to re-bake the VoxelGI data because it won't be able to load the old GIProbeData from the new mesh format MRP.

[novemberist]

So, as of commit #49547 by @reduz the blackness is gone and VoxelGI seems to somewhat work again. However, this is only the case if you set "Global Illumination" for your MeshInstance to "baked". If you select "dynamic" here, once you bake the GIData, Godot slows down permanently (almost freezes). If I understand the current GI implementations correctly, the gi_mode "baked" should only be relevant for LightmapGI (and thus have no effect for VoxelGI) whereas "dynamic" is the correct one to enable if you want the Mesh to contribute to VoxelGI? I think something is still broken here (or it is really a driver issue)

[Calinou]

If I understand the current GI implementations correctly, the gi_mode "baked" should only be relevant for LightmapGI (and thus have no effect for VoxelGI)

AFAIK, Baked and Dynamic are treated differently in VoxelGI, and both are meant to work with VoxelGI.

[William-Godwin]

However, this is only the case if you set "Global Illumination" for your MeshInstance to "baked". If you select "dynamic" here, once you bake the GIData, Godot slows down permanently (almost freezes).

It's still happening for me on Win and linux with GTX 1080 on Hugo's builds. =(

[Calinou]

Closing in favor of #55359, which describes the issue at hand in more detail. The unexpectedly low performance only occurs with meshes in Dynamic bake mode, not the Baked bake mode.