Viewport performance drops drastically after switching from atributte visualization to solid view #93440

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: AMD Radeon RX 5700 XT ATI Technologies Inc. 4.5.14802 Core Profile Context 21.11.2 30.0.14005.1000

Blender Version
Broken: version: 3.0.0 Release Candidate, branch: master, commit date: 2021-11-25 17:24, hash: 2fb8c6805a

Short description of error

I have a curve with an specific setup of geometry nodes, that for some reason, if I go from solid mode->eevee->solid mode again, it slow downs performance drasticaly for no reason.
The problem also occurs on objects that contain Sculpt Vertex Colors.

Exact steps for others to reproduce the error

Open the file, switch to rendered view and then back to solid view. note that if you go back to eevee again the performace gets back to normal.

In the video below you can see the fps dropping in the corner. It wasn't recorded with default settings, but I tried restoring them and it gave me the same result

2021-11-27 20-52-26.mp4
geometry nodes slowdown.blend

Notes:

The problems seems to someway be related to the attributes that are being used in shader nodes or that are being visualized via vertex colors.
The amount of performance drop depends on the type of the attribute and where its stored.
It does trigger after using EEVEE or visualizing the vertex colors in Solid view, but it does not happens after switching from Cycles
in the case of Sculpt vertex colors, the performance drop stops if you change to sculpt mode

Added subscriber: @Diogo_Valadares

#96003 was marked as duplicate of this issue

#95766 was marked as duplicate of this issue

Added subscriber: @deadpin

Changed status from 'Needs Triage' to: 'Confirmed'

Confirmed here too. Toggling the GN modifier off/on will also return performance back to normal.

Added subscriber: @costa

Confirmed here too

Added subscriber: @lowpolysaac

This comment was removed by @lowpolysaac

Added subscriber: @HooglyBoogly

If I apply the modifier, I can still reproduce this issue, so I don't think it's related to geometry nodes.

What I did find is that the tangents are being recalculated on every redraw, with blender::draw::extract_tan_ex_init being the main performance culprit here. I'm guessing that switching between EEVEE and workbench somehow messes up the mesh data extraction system. But I don't know much about that area.

I just got the same problem problem with another file(blender 3.1 alpha):
slowdown2.blend

If I apply the modifier, I can still reproduce this issue, so I don't think it's related to geometry nodes.

How did you apply the modifier? Converting it to mesh fixes the problem for me, I can't directly apply the modifier because its a curve and it contains construtive stuff and using a mesh as input and converting it to curves in geometry nodes also doesn't cause me problems.

Added subscriber: @EAW

Reminds me of #78161 (Workbench refactor causes significant performance regression with workbench shadows). I wonder if there is something in Workbench’s code making it susceptible to have updates get called way too often.

In #93440#1280689, @Diogo_Valadares wrote:

If I apply the modifier, I can still reproduce this issue, so I don't think it's related to geometry nodes.

How did you apply the modifier? Converting it to mesh fixes the problem for me

Ah, right, yes, I meant that I converted the object to a mesh object. That also initially fixed the problem for me, but then I toggled render and workbench a few more times and the problem came back.

I decided to test this a little bit more and I found some things that might be what is causing the problem.

In both geometry nodes I sent, I'm transfering some attributes to the output of the geometry nodes, and right after I use them on the shader nodes.

Once I remove the attribute groups from the output, the problem doesn't happen anymore. Also, if the groups aren't being used by the shader, the problem does not occur too.

After applying the modifier the problem still occurs because the attributes are still stored on the mesh. Btw I don't know why but it also create those "anonymous attributes" that are the outputs of the geometry nodes even tho those attributes already exist with another name(but I think this is an unrelated problem)

Once you remove the atributes the problem does not occur anymore.

And after a close look I think the type of the attribute and where its stored makes a huge difference on how much the performance is affected. You can take a look at the first example, the only attribute being used is a generated "uvmap" that is a vector stored on face corners, and even tho its much simpler and less poly dense than the second file, it takes the fps to 6. the second file contains 5 float attributes stored on vertices and still have decent fps.

Just noticed today that this glitch also occurs when using the Experimental Sculpt Vertex Colors, since its stored in attributes.

If stored to reguler vertex colors, it does not affect performance, even tho its seems to also be kept in the attributes.

It seems like it doesn't even need to be in eevee for the performance to be affected. If you switch to vertex visualization in the regular solid view and then switch back, it also reduces the performance.

2022-01-12 13-08-55.mp4

Added subscriber: @lictex_1

Added subscribers: @Rawalanche, @PratikPB2123

Added subscriber: @Olliver

With #96003 being fixed I tested to see if the problem here was also fixed, and it seems so.

I tested in both 3.1 and 3.2 alpha but I'd like some confirmation for that in case I tested something wrong.

should be a911f075d7 fixed this

Changed status from 'Confirmed' to: 'Resolved'

should be a911f075d7 fixed this

I guess this task can be closed then.

Added subscriber: @GaryRitchie

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Viewport performance drops drastically after switching from atributte visualization to solid view #93440