Rendering time increasing when Viewport Shading in Rendered mode after it stop to compute #82917

New Issue

Eugene Du · 2020-11-22T10:48:18+01:00

Eugene Du commented

2020-11-22 10:48:18 +01:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1650 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71

Blender Version
Broken: version: 2.90.1, branch: master, commit date: 2020-09-23 06:43, hash: 3e85bb34d0 also 2.83.5

Short description of error
Rendering time increasing when Viewport Shading in Rendered mode after it stop to compute.

Exact steps for others to reproduce the error
Test scene
https://cloud.blender.org/p/gallery/5f4cd4441b96699a87f70fcb

Make sure you use only GPU in Pref - System - CUDA
Switch Render Engine to Cycles - GPU Compute
Change View to Solid this time and hit F12.
Remember rendering time.
Change View to Rendered.
Wait until it stop to compute in viewport and then
Hit F12 and watch how rendering become slow…

Results:
2.83.5 - F12 from Solid View - Rendering Time - 3:29

2.83.5 - F12 from Rendered View (after it stop to compute) - Rendering Time - 5:47

2.90.1 - F12 from Solid View - Rendering Time - 3:28

2.90.1 - F12 from Rendered View (after it stop to compute) - Rendering Time - 5:46

if you already know about this issue, you can make a checking when pressing F12, if in Solid view then render, if Rendered view then go to Solid and render.

In some cases, I don't know yet how to reproduce, rendering time become insane like this

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1650 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71 **Blender Version** Broken: version: 2.90.1, branch: master, commit date: 2020-09-23 06:43, hash: `3e85bb34d0` also 2.83.5 **Short description of error** Rendering time increasing when Viewport Shading in Rendered mode after it stop to compute. **Exact steps for others to reproduce the error** Test scene https://cloud.blender.org/p/gallery/5f4cd4441b96699a87f70fcb 0. Make sure you use only GPU in Pref - System - CUDA 1. Switch Render Engine to Cycles - GPU Compute 2. Change View to Solid this time and hit F12. 3. Remember rendering time. 4. Change View to Rendered. 5. Wait until it stop to compute in viewport and then 6. Hit F12 and watch how rendering become slow… Results: 2.83.5 - F12 from Solid View - Rendering Time - 3:29 ![2.83 test1.png](https://archive.blender.org/developer/F9353392/2.83_test1.png) 2.83.5 - F12 from Rendered View (after it stop to compute) - Rendering Time - 5:47 ![2.83 test2.png](https://archive.blender.org/developer/F9353397/2.83_test2.png) 2.90.1 - F12 from Solid View - Rendering Time - 3:28 ![2.90.1 test1.png](https://archive.blender.org/developer/F9353402/2.90.1_test1.png) 2.90.1 - F12 from Rendered View (after it stop to compute) - Rendering Time - 5:46 ![2.90.1 test2.png](https://archive.blender.org/developer/F9353404/2.90.1_test2.png) if you already know about this issue, you can make a checking when pressing F12, if in Solid view then render, if Rendered view then go to Solid and render. In some cases, I don't know yet how to reproduce, rendering time become insane like this ![test2.png](https://archive.blender.org/developer/F9353433/test2.png)

Eugene Du commented

2020-11-22 10:48:18 +01:00

Added subscriber: @APEC

Eugene Du commented

2020-11-22 11:03:03 +01:00

just tested 2.91 and it's the same

Jeroen Bakker commented

2020-11-23 09:07:46 +01:00

Added subscriber: @Jeroen-Bakker

Jeroen Bakker commented

2020-11-23 09:07:46 +01:00

Even when the viewport is finished rendering it still keeps all data around for quick scene updates. This means that memory on the GPU is still allocated. Could it be that in your test your RAM or GPURAM is full so it needs to swap? Or doesn't have enough head room to optimize.

Eugene Du commented

2020-11-23 09:27:04 +01:00

Yes you are right! Didn't even think about it ...
VRAM for Eevee is 1.6/4Gb
VRAM for Cycles is 3.6/4Gb

This is why I recommend adding a check if the VRAM is less than half, then free it by switching to Solid view before rendering to prevent this issue.
Hope developers before close this task add reminder to their notes TODO.

Yes you are right! Didn't even think about it ... VRAM for Eevee is 1.6/4Gb VRAM for Cycles is 3.6/4Gb This is why I recommend adding a check if the VRAM is less than half, then free it by switching to Solid view before rendering to prevent this issue. Hope developers before close this task add reminder to their notes TODO.

Richard Antalik commented

2020-12-07 09:01:14 +01:00

Added subscriber: @iss

Richard Antalik commented

2020-12-07 09:01:14 +01:00

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

Richard Antalik closed this issue

2020-12-07 09:01:14 +01:00

Richard Antalik commented

2020-12-07 09:01:14 +01:00

@APEC Thank you for report. Currently we don't consider out of memory situations to be a bug. Since this is design feature rather than limitation I don't think we can classify this as known issue either.

@Jeroen-Bakker feel free to reopen as known issue if you disagree with me.

@APEC Thank you for report. Currently we don't consider out of memory situations to be a bug. Since this is design feature rather than limitation I don't think we can classify this as known issue either. @Jeroen-Bakker feel free to reopen as known issue if you disagree with me.

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Rendering time increasing when Viewport Shading in Rendered mode after it stop to compute #82917