Performance issues

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phoenixart
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Performance issues

Post by phoenixart » Fri Aug 28, 2020 2:08 am

When I have the viewport shading in rendered mode active, navigating around becomes quite sluggish. I've been able to get some minor improvement by locking the camera to view, previewing only the camera bounds area, and excluding the rest of the viewport area. Unfortunately, that's not enough as I still cannot exactly move around in the viewport without causing a continuous delay in the operations I'm doing.

A similar issue occurs when I tweak any parameter, from materials to lights, render settings, and so on.

On top of that, when I switch to shading rendered mode or I render an image, my PC fans kick in quite bad, something I'm not experiencing with other render engines or software (Cycles, C4D, Redshift)

I wonder if this is to be expected or there's some particular hardware related known bug.

This is my configuration:

Threadripper 1950 x
64 GB Ram
NVME 500 GB Toshiba + SSD 2 TB Samsung
Dual GeForce 1080ti (drivers 452.06)
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Dade
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Re: Performance issues

Post by Dade » Fri Aug 28, 2020 12:17 pm

It is hard to make any comment without knowing the scene complexity, the rendering resolution, CPU or GPU rendering, etc. A video and posting test scene could help.
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phoenixart
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Re: Performance issues

Post by phoenixart » Fri Aug 28, 2020 9:19 pm

Thanks, Dade

Unfortunately, this is happening regardless of the scene's complexity.
A simple cube and the default light already causes the issue.

I'll try to post a video later.
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Re: Performance issues

Post by phoenixart » Fri Aug 28, 2020 10:56 pm

Here's a very basic example showing LuxCore and Cycles

LuxCore
https://drive.google.com/file/d/1KbRYRK ... sp=sharing

Cycles
https://drive.google.com/file/d/1FE5p9d ... sp=sharing

Both video have been recorded with the same conditions, meaning the same apps running in the background (mostly OS services/utilities).
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B.Y.O.B.
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Re: Performance issues

Post by B.Y.O.B. » Sat Aug 29, 2020 10:53 am

Weird, this horizontal division is something I've never seen before.
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Dade
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Re: Performance issues

Post by Dade » Sat Aug 29, 2020 1:10 pm

B.Y.O.B. wrote:
Sat Aug 29, 2020 10:53 am
Weird, this horizontal division is something I've never seen before.
They are the GPUs tiles, he has 2xGPU.
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Re: Performance issues

Post by B.Y.O.B. » Sat Aug 29, 2020 2:35 pm

Ah, right, I didn't remember that RTPathOCL can use multiple GPUs.

@phoenixart: Does the behaviour get better when using only one GPU?
Or when switching to CPU only?

It might be related to this issue: https://github.com/LuxCoreRender/BlendL ... issues/527

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Dade
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Re: Performance issues

Post by Dade » Sat Aug 29, 2020 3:50 pm

B.Y.O.B. wrote:
Sat Aug 29, 2020 2:35 pm
It might be related to this issue: https://github.com/LuxCoreRender/BlendL ... issues/527

No, there is not HDR, it may be related to this: https://github.com/LuxCoreRender/BlendL ... issues/521
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Re: Performance issues

Post by B.Y.O.B. » Sat Aug 29, 2020 4:19 pm

Dade wrote:
Sat Aug 29, 2020 3:50 pm
No, there is not HDR, it may be related to this: https://github.com/LuxCoreRender/BlendL ... issues/521
That's only about final render though, and the Blender API for final render framebuffer transfer. Viewport renders copy directly to bgl.Buffer.

So it might be unrelated to previous problems.

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Re: Performance issues

Post by phoenixart » Sat Aug 29, 2020 6:33 pm

I tried with CPU only and the split-screen effect is gone. The performance hasn't improved much, though
The same happens using 1 GPU only, no split-screen, and performance is just about the same.
Here's a screen capture
https://drive.google.com/file/d/1u7wDf5 ... sp=sharing
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