Cycles SVM Stack full with relatively few nodes #117706

New Issue

Open

opened 2024-01-31 23:59:06 +01:00 by Zach Eastin · 9 comments

Zach Eastin commented

2024-01-31 23:59:06 +01:00

System Information
Operating system: Windows-10-10.0.22621-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 551.23

Blender Version
Broken: version: 4.1.0 Alpha, branch: main, commit date: 2024-01-31 09:40, hash: 58ceeee6f406
Worked: 4.0

Short description of error
I have an addon that effectively allows for layering and procedural editing of pbr texture sets to create new materials. This naturally can lead to many many nodes leading to an SVM Stack Space error. However, this is only in Blender 4.1 and wasn't present in 4.0. I have significantly parred down the nodes to a fairly reasonable amount and am still receiving the SVM error.

Exact steps for others to reproduce the error
Open attached blend file. Go into render mode in viewport. Cube will be black though if you mute (almost) any node you will see the bump result. Included a debugging node at the end to ensure that the value going into the bump node isn't just 0.

**System Information** Operating system: Windows-10-10.0.22621-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 551.23 **Blender Version** Broken: version: 4.1.0 Alpha, branch: main, commit date: 2024-01-31 09:40, hash: `58ceeee6f406` Worked: 4.0 **Short description of error** I have an addon that effectively allows for layering and procedural editing of pbr texture sets to create new materials. This naturally can lead to many many nodes leading to an SVM Stack Space error. However, this is only in Blender 4.1 and wasn't present in 4.0. I have significantly parred down the nodes to a fairly reasonable amount and am still receiving the SVM error. **Exact steps for others to reproduce the error** Open attached blend file. Go into render mode in viewport. Cube will be black though if you mute (almost) any node you will see the bump result. Included a debugging node at the end to ensure that the value going into the bump node isn't just 0.

svm_error.blend

363 KiB

Zach Eastin added the

labels 2024-01-31 23:59:07 +01:00

Iliya Katushenock added the

Render & Cycles

label 2024-02-01 01:23:50 +01:00

Iliya Katushenock commented

2024-02-01 01:29:40 +01:00

Member

This looks like expected limitation, your node groups have too many things still.
As i can see, this related with Bump node, this might be mean that your shader is used multiple time to compute result value of normal.

There is one error: ERROR (bke.lib_id): C:\Users\blender\git\blender-vdev\blender.git\source\blender\blenkernel\intern\lib_id.cc:338 id_us_min: ID user decrement error: MATrue-Terrain Material (from '[Main]'): 0 <= 0, not sure how you did that, and not sure if this might cause any related issue, but just to note.

This looks like expected limitation, your node groups have too many things still. As i can see, this related with `Bump` node, this might be mean that your shader is used multiple time to compute result value of normal. There is one error: `ERROR (bke.lib_id): C:\Users\blender\git\blender-vdev\blender.git\source\blender\blenkernel\intern\lib_id.cc:338 id_us_min: ID user decrement error: MATrue-Terrain Material (from '[Main]'): 0 <= 0`, not sure how you did that, and not sure if this might cause any related issue, but just to note.

Pratik Borhade commented

2024-02-01 04:35:44 +01:00

Member

Hi, thanks for the report. This is expected behavior. Svm stack can hold upto 256 nodes. Your node tree has many nodes, hence the error.
Though this won't happen if you render with CPU+OSL. @Alaska explained the situation in details at #115459, closing.

Hi, thanks for the report. This is expected behavior. Svm stack can hold upto 256 nodes. Your node tree has many nodes, hence the error. Though this won't happen if you render with CPU+OSL. @Alaska explained the situation in details at #115459, closing.

Pratik Borhade closed this issue

2024-02-01 04:35:47 +01:00

Blender Bot added

and removed

labels 2024-02-01 04:35:49 +01:00

Zach Eastin commented

2024-02-01 16:46:15 +01:00

Author

Apologies for being maybe a bit of a pain but I think this is different than #115459 . Though, and maybe I just missed the explanation, if I'm hitting the max of 256 nodes shouldn't that limit be reached in both Blender 4.0 and Blender 4.1?

Also, how come in this new file I'm attaching if I don't use any boolean group inputs it seems to work?

Like I said before, I have an addon that has added, and Blender has been fine with, significantly more nodes than what is in these test blends and I mean like hundreds of nodes more. The original blend file had probably around a hundred or more nodes removed from it that weren't effecting the svm error to help you all out. This new blend file attached has more nodes than the original one but still works. I say all this in hopes to peak your interest in opening this back up.

Apologies for being maybe a bit of a pain but I think this is different than #115459 . Though, and maybe I just missed the explanation, if I'm hitting the max of 256 nodes shouldn't that limit be reached in both Blender 4.0 and Blender 4.1? Also, how come in this new file I'm attaching if I don't use any boolean group inputs it seems to work? Like I said before, I have an addon that has added, and Blender has been fine with, significantly more nodes than what is in these test blends and I mean like hundreds of nodes more. The original blend file had probably around a hundred or more nodes removed from it that weren't effecting the svm error to help you all out. This new blend file attached has more nodes than the original one but still works. I say all this in hopes to peak your interest in opening this back up.

svm_error_no_bool_test.blend

415 KiB

Zach Eastin reopened this issue

2024-02-01 16:46:19 +01:00

Blender Bot added

and removed

labels 2024-02-01 16:46:20 +01:00

Iliya Katushenock commented

2024-02-01 16:56:31 +01:00

Member

@Alaska hi, might you know something about that?/

@Alaska hi, might you know something about that?/

Zach Eastin commented

2024-02-01 18:17:36 +01:00

Author

Okay, sorry, just to add some more info. Here's one more blend file. For the last blend file I duplicated a group node that used Boolean sockets and just deleted all boolean sockets from a copy of the group node(s). In this one, that node group (No Bool) is still there, along with the original node group (Uses Bool), but I then duplicated Uses Bool again but this time converted the boolean group sockets to floats (Uses Floats) and it also seems to work. Also, there is something interesting with what of the 3 group nodes are connected. If No Bool is connected along with Uses Bool, Uses Bool will not work. However, if Uses Floats and Uses Bool are the only ones connected, Uses Bool works fine.

Okay, sorry, just to add some more info. Here's one more blend file. For the last blend file I duplicated a group node that used Boolean sockets and just deleted all boolean sockets from a copy of the group node(s). In this one, that node group (`No Bool`) is still there, along with the original node group (`Uses Bool`), but I then duplicated `Uses Bool` again but this time converted the boolean group sockets to floats (`Uses Floats`) and it also seems to work. Also, there is something interesting with what of the 3 group nodes are connected. If `No Bool` is connected along with `Uses Bool`, `Uses Bool` will not work. However, if `Uses Floats` and `Uses Bool` are the only ones connected, `Uses Bool` works fine. <div id="image-table"> <table> <tr> <td style="padding:10px"> <img src="/attachments/582586c0-0a64-4971-97bb-253f59e69ce0" width="400"/> </td> <td style="padding:10px"> <img src="/attachments/4784db8f-226f-490a-afc7-04e733206d9d" width="400"/> </td> </tr> </table> </div>

1.7 MiB

1.9 MiB

svm_error_uses_floats_test.blend

470 KiB

Alaska commented

2024-02-01 21:04:34 +01:00

Member

As Sergey shared in another report. The way the node graph is added to the SVM stack is non-deterministic. So a path that could be easily optimized out if the graph is computed one way may not work computed a different way. Along with that, versioning code in Blender 4.1 may change the node setup of files from Blender 4.0.

I don't think there's any versioning code for Blender 4.1 that should impact this file (but I may be wrong). And I don't know enough about the exact way the SVM Stack is constructed to know why connecting No Bool and Use Bools causes issues while other combinations doesn't. It's probably the "non-deterministic" behaviour that's causing that.

Anyway, it's probably better to get this looked at by someone else. See if it's a bug or just mark it as a known issue with "SVM has some issues, and this is one of them, we hope to improve it in the future."

As Sergey shared in another report. The way the node graph is added to the SVM stack is non-deterministic. So a path that could be easily optimized out if the graph is computed one way may not work computed a different way. Along with that, versioning code in Blender 4.1 may change the node setup of files from Blender 4.0. I don't think there's any versioning code for Blender 4.1 that should impact this file (but I may be wrong). And I don't know enough about the exact way the SVM Stack is constructed to know why connecting `No Bool` and `Use Bools` causes issues while other combinations doesn't. It's probably the "non-deterministic" behaviour that's causing that. Anyway, it's probably better to get this looked at by someone else. See if it's a bug or just mark it as a known issue with "SVM has some issues, and this is one of them, we hope to improve it in the future."

Pratik Borhade commented

2024-02-02 05:34:27 +01:00

Member

Still looks expected since the nodetree has nested node groups with many nodes.
Given that 4.0 works, I did some checks, some commit between a935701a872d - 4050b0d6dfdb caused this.
@lichtwerk hi, can you help is bisecting?

Still looks expected since the nodetree has nested node groups with many nodes. Given that 4.0 works, I did some checks, some commit between `a935701a872d - 4050b0d6dfdb` caused this. @lichtwerk hi, can you help is bisecting?

Pratik Borhade added

Render & Cycles

and removed

Render & Cycles

labels 2024-02-02 05:39:46 +01:00

Pratik Borhade commented

2024-02-07 07:36:35 +01:00

Member

Raising priority for awareness.

Raising priority for awareness.

Pratik Borhade added

and removed

labels 2024-02-07 07:36:47 +01:00

Zach Eastin commented

2024-02-07 21:13:10 +01:00

Author

Hopefully some helpful information. Removing the boolean and integer sockets from our shader groups seems to have removed the svm issue entirely and are easily able to add all node groups we wish to.

Hopefully some helpful information. Removing the boolean and integer sockets from our shader groups seems to have removed the svm issue entirely and are easily able to add all node groups we wish to.

Brecht Van Lommel added

and removed

labels 2024-02-28 17:18:02 +01:00

Sign in to join this conversation.

No Label

Animation & Rigging

Asset Browser Project Overview

Automated Testing

Blender Asset Bundle

Dependency Graph

Development Management

EEVEE & Viewport

Images & Movies

Motion Tracking

Nodes & Physics

Pipeline, Assets & IO

Platforms, Builds & Tests

Render & Cycles

Render Pipeline

Sculpt, Paint & Texture

Video Sequencer

Virtual Reality

Blender 2.8 Project

Milestone 1: Basic, Local Asset Browser

Good First Issue

Animation & Rigging

Development Management

EEVEE & Viewport

Nodes & Physics

Pipeline, Assets & IO

Platforms, Builds & Tests

Render & Cycles

Sculpt, Paint & Texture

Needs Info from Developers

Needs Information from User

No Milestone

No project

No Assignees

4 Participants

Notifications

Due Date

The due date is invalid or out of range. Please use the format 'yyyy-mm-dd'.

No due date set.

Dependencies

No dependencies set.

Reference: blender/blender#117706

No description provided.