Significant performance drop when changing the active render slot in 3.5 #107200

New Issue

chaos · 2023-04-21T00:09:39+02:00

chaos commented

2023-04-21 00:09:39 +02:00

System Information
Operating system: Linux-5.4.0-105-generic-x86_64-with-glibc2.31 64 Bits
Graphics card: NVIDIA GeForce RTX 3080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 525.85.05

Blender Version
Broken: version: 3.5.0, branch: blender-v3.5-release, commit date: 2023-03-29 02:56, hash: 1be25cfff18b
Worked: version: 3.4.0, stable release

Description
There has been an important slowdown in the time it takes for Blender to set the active render slot in the last stable release of Blender 3.5, the performance was much better in Blender 3.4.
The size of the region area being shown in the UI seems to have something to do with this performance penalty.

I'm including a simple blend file with a test script to compare the times, so check the attachment.
The script adds a test modal operator that runs a fast timer and sets the active render slot in every modal loop.
The time is measured between every loop to get an idea of the FPS speed, and then this is shown in the area's header.

Exact steps for others to reproduce the error
You should repeat this test in Blender 3.5 and 3.4:

Open the blendfile
Run the script in the Text Editor
Put the cursor in the Image Editor with the Render Result image selected
Press F3 to search and run the operator "test.test". The FPS is now shown in the area's header
You can now change the size of the current Image Editor area while running the modal operator, for example, by dragging the area's border to change the size horizontally.
This introduces the performance penalty, and you can see the reduction in FPS as the Image area gets bigger. When reducing the Image area, the speed increases again.
This doesn't seem to happen in Blender 3.4, or at least it's imperceptible to me. In 3.4, the Image area can even be at fullscreen and I still can't see a reduction in speed, while in 3.5 the CPU works a lot harder and I can only get the same performance when reducing the size of the area up to a quarter compared to the original from 3.4.
Exit the modal loop with Esc key

What's the significance for the time it takes to set a render slot you may ask, and the thing is that I have a script that can change the slots rapidly, temporarily generating an animation with them, without having to export or save the frames. In the current state, it has just became too slow for that.

**System Information** Operating system: Linux-5.4.0-105-generic-x86_64-with-glibc2.31 64 Bits Graphics card: NVIDIA GeForce RTX 3080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 525.85.05 **Blender Version** Broken: version: 3.5.0, branch: blender-v3.5-release, commit date: 2023-03-29 02:56, hash: `1be25cfff18b` Worked: version: 3.4.0, stable release **Description** There has been an important slowdown in the time it takes for Blender to set the active render slot in the last stable release of Blender 3.5, the performance was much better in Blender 3.4. The size of the region area being shown in the UI seems to have something to do with this performance penalty. I'm including a simple blend file with a test script to compare the times, so check the attachment. The script adds a test modal operator that runs a fast timer and sets the active render slot in every modal loop. The time is measured between every loop to get an idea of the FPS speed, and then this is shown in the area's header. **Exact steps for others to reproduce the error** You should repeat this test in Blender 3.5 and 3.4: - Open the blendfile - Run the script in the Text Editor - Put the cursor in the Image Editor with the Render Result image selected - Press F3 to search and run the operator "test.test". The FPS is now shown in the area's header - You can now change the size of the current Image Editor area while running the modal operator, for example, by dragging the area's border to change the size horizontally. This introduces the performance penalty, and you can see the reduction in FPS as the Image area gets bigger. When reducing the Image area, the speed increases again. This doesn't seem to happen in Blender 3.4, or at least it's imperceptible to me. In 3.4, the Image area can even be at fullscreen and I still can't see a reduction in speed, while in 3.5 the CPU works a lot harder and I can only get the same performance when reducing the size of the area up to a quarter compared to the original from 3.4. - Exit the modal loop with Esc key What's the significance for the time it takes to set a render slot you may ask, and the thing is that I have a script that can change the slots rapidly, temporarily generating an animation with them, without having to export or save the frames. In the current state, it has just became too slow for that.

slot_test-blender_3.5.blend

845 KiB

chaos added the

labels 2023-04-21 00:09:40 +02:00

Pratik Borhade commented

2023-04-21 08:04:55 +02:00

Hi, thanks for the report. Maybe this is fixed already along with #106092
Can you check again in 3.6 build?: https://builder.blender.org/download/daily/

Hi, thanks for the report. Maybe this is fixed already along with #106092 Can you check again in 3.6 build?: https://builder.blender.org/download/daily/

Pratik Borhade added

Status

Needs Information from User

and removed

Status

Needs Triage

labels 2023-04-21 08:05:03 +02:00

chaos commented

2023-04-22 05:00:38 +02:00

I can confirm that the performance has come back to normal in current 3.6 build.
No noticeable difference with 3.4.
Problem solved, thank you so much!

I can confirm that the performance has come back to normal in current 3.6 build. No noticeable difference with 3.4. Problem solved, thank you so much!

Pratik Borhade commented

2023-04-22 05:27:21 +02:00

Closing then.

Pratik Borhade closed this issue

2023-04-22 05:27:23 +02:00

Blender Bot added

Status

Archived

and removed

Status

Needs Information from User

labels 2023-04-22 05:27:25 +02:00