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Won't Fix

Votes

4

Found in

2021.3.20f1

2022.3.39f1

6000.0.0b11

6000.1.0a7

6000.2.0a1

7000.0.0a1

Issue ID

UUM-29294

Regression

No

[Win] Editor slows down on each subsequent run when using compute shaders

-

Reproduction steps:
1. Open the attached “Repro.zip” project
2. Open the “Assets/Tutorial01.unity” Scene
3. Enter the Play Mode
4. Observe the FPS in the Game View’s Status window
5. Exit the Play Mode
6. Repeat the 3-5 steps

Expected result: Performance always stays the same
Actual result: Significant performance decrease each subsequent time the Play Mode is entered

Reproducible with: 2021.3.20f1, 2022.2.9f1, 2023.1.0b6, 2023.2.0a4
Couldn’t test with: 2020.3.45f1 (Errors in the Scripts due to missing/changed features)

Reproducible on: M1 macOS 13.1, Windows 10 (21H2)

Note: The issue is reproducible on both Intel and Apple Silicon Editors on M1 Mac

  1. Resolution Note:

    The issue appears to be in the user code. Looking at a graphics capture of the rendering one can see that both the compute shader work group count and the indirect draw instance count are increasing on each consecutive playmode enter. We can not spend time debugging user code too much but there were definitely signs of potential mistakes there. For example the arguments buffers are uninitialized for the first dispatches. Also the read/write buffer index handling looks buggy. So most likely something in the user code that is triggering the counts to be increasing each play, thus increasing the GPU load and decreasing the performance.

Comments (1)

  1. Sulfield

    Mar 27, 2023 12:52

    Is there by any chance an estimate when you're going to look into this issue / whether it's addressable in the short term? We'll need to plan our roadmap accordingly and also estimate how to deal with the current situation, which is quite limiting.

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