Compositor - Extreme performance degradation requiring Blender restart after approx. 1 minute #118459

New Issue

michael campbell · 2024-02-19T16:11:39+01:00

michael campbell commented

2024-02-19 16:11:39 +01:00

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 537.58

Blender Version
Broken: version: 4.2.0 Alpha, branch: main, commit date: 2024-02-16 21:52, hash: 8b6d145a6b04
Worked: (unknown)

Short description of error
Within one minute Blender requires restart due to severe performance degradation under below circumstances if image editor is set to viewer or compositor backdrop is enabled.

Exact steps for others to reproduce the error
with all of the below, open with the 'load ui' option enabled for easier replication.

test 1 (demonstrates issue not present if only updating the image datablocks filepath)

open 'only update image is fine.blend'
run the script
start playback, take a note of the fps, then leave playing for 30 seconds.
image will be updating in the image editor's viewer mode and compositor's backdrop.
check fps (should match original)

test 2 (demonstrating issue is not present with only calling render.render)

open 'render.redner on own is fine.blend'
run the script
start playback, take a note of the fps, then leave playing for 30 seconds.
compositor is calculating and the file output node is generating files to the //out directory.
check fps (should match original)

test 3 (demonstrates the bug)

open 'repeated call to render.render with image update leads to performance degredation.blend'
run the script and make sure the image editor is not set to viewer, and the compositor backdrop is disabled.
start playback, take a note of the fps, then leave playing for 30 seconds.
check fps. Should match original with no performance degredation, even though the compositor was being executed as you can tell by the images being generated into the //out folder.
now either change the image editor to viewer node, or turn on the compositor's backdrop
start playback, take a note of the fps, then leave playing for 30 seconds.
Blender is now unusably slow as a result of enabling the backdrop or viewer mode of the image editor, even though the actual work being performed by the compositor has not changed.
Open one of the previous blend files without restarting blender.
run the script
Playback is still slow even though the handlers weren't persistent between file opens
Restart Blender
test one of the first two files again and performance will be back.

Perhaps some image datablock variable is not being cleared if render.render is called directly after changing the image filepath, leading to multiple calls to the same function when it only needs to happen once?

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 537.58 **Blender Version** Broken: version: 4.2.0 Alpha, branch: main, commit date: 2024-02-16 21:52, hash: `8b6d145a6b04` Worked: (unknown) **Short description of error** Within one minute Blender requires restart due to severe performance degradation under below circumstances if image editor is set to viewer or compositor backdrop is enabled. **Exact steps for others to reproduce the error** with all of the below, open with the 'load ui' option enabled for easier replication. test 1 (demonstrates issue not present if only updating the image datablocks filepath) 1. open 'only update image is fine.blend' 2. run the script 3. start playback, take a note of the fps, then leave playing for 30 seconds. 4. image will be updating in the image editor's viewer mode and compositor's backdrop. 5. check fps (should match original) test 2 (demonstrating issue is not present with only calling render.render) 1. open 'render.redner on own is fine.blend' 2. run the script 3. start playback, take a note of the fps, then leave playing for 30 seconds. 4. compositor is calculating and the file output node is generating files to the //out directory. 4. check fps (should match original) test 3 (demonstrates the bug) 1. open 'repeated call to render.render with image update leads to performance degredation.blend' 2. run the script and make sure the image editor is not set to viewer, and the compositor backdrop is disabled. 3. start playback, take a note of the fps, then leave playing for 30 seconds. 4. check fps. Should match original with no performance degredation, even though the compositor was being executed as you can tell by the images being generated into the //out folder. 5. now either change the image editor to viewer node, or turn on the compositor's backdrop 6. start playback, take a note of the fps, then leave playing for 30 seconds. 7. Blender is now unusably slow as a result of enabling the backdrop or viewer mode of the image editor, even though the actual work being performed by the compositor has not changed. 8. Open one of the previous blend files without restarting blender. 9. run the script 10. Playback is still slow even though the handlers weren't persistent between file opens 11. Restart Blender 12. test one of the first two files again and performance will be back. Perhaps some image datablock variable is not being cleared if render.render is called directly after changing the image filepath, leading to multiple calls to the same function when it only needs to happen once?

cycles performance degredation.rar

4.5 MiB

michael campbell added the

labels 2024-02-19 16:11:40 +01:00

michael campbell changed title from ~~Extreme performance degradation requiring Blender restart after approx. 1 minute~~ to Compositor - Extreme performance degradation requiring Blender restart after approx. 1 minute

2024-02-20 18:09:17 +01:00

Pratik Borhade commented

2024-03-14 08:17:22 +01:00

Thanks for the report. I can confirm the performance degradation when image updates per frame and render call is sent.
cc @OmarEmaraDev

Thanks for the report. I can confirm the performance degradation when image updates per frame and render call is sent. cc @OmarEmaraDev

Pratik Borhade added

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Compositor - Extreme performance degradation requiring Blender restart after approx. 1 minute #118459