Denoiser issue

The GPU usage is clear to me.
I talk about the CPU usage.

The same CPU usage is seen in V7 when using Raytraced in the viewport.

Please try Raytraced in V6.
And view CPU load.
Then see in V7.

V6 uses “no” CPU, V7 uses “all” CPU.

I’ll check in a few days when back at work from vacation.,

Actually, I was confusing the right-hand side graph for the CPU, but that is the CUDA usage, mobile phone display was a bit too small to properly see :slight_smile: . There is indeed some CPU usage, and I’m going to guess that it is related to the post-effects and handling of the viewport update that is causing the slight increase of CPU, but nothing really dramatic.

Slight…no that’s not slight.
Try Raytraced in V7 and zoom in and out while Cycles works.
I see up to 100% CPU load on a 12 core CPU.
That is quite different in V6.
It is dramatic…

I am seeing around 50% CPU load when Raytraced is running here too.
V7 on a dual 6 core Xeon (=total of 12 cores and 24 threads)

Intel denoiser turned on in render settings.

When in Rendered mode and Rhino idle in the background the CPU load is 6%.
When I turn off Rhino it drops to 2%.

That is with the intel denoiser turned off.

File saved and reopened and idle CPU load is 2%.

When Raytraced view is activated it is now around 50% CPU load again (intel denoiser still off)
When Raytraced is competed (100 of 100 cycles) the cpu idles at 6% again.
And NOW when switched to Rendered it drops down to 2% again.

So cycles seems to hog some cpu usage even when idle, and if the intel denoiser was used it continues to hog those resorses even after raytraced is turned off.

Edit: I restart Rhino after each change to make sure nothing is left unchanged.

Tried with the nvidia denoiser now and then the cpu is used 50% when rendering and idles at 11% when completed. And goes down to 6% when switched to rendered mode. So still hogging resources.

On restart with no denoiser I see the same again, when Raytraced it uses 50% cpu load and drops to 6% cpu when completed, and again drops to 2% when switched to Rendered.

RH-59694 is fixed in the latest WIP

I’m still going to guestimate it has to do with the changes introduced for the post effect pipeline.

There were 2 issues:

  1. CPU load after denoise
    This is fixed in the current WIP.

  2. CPU load while Cycles works
    Still there.
    I found out that the CPU load increases when you zoom out.

(7.0.20231.16005, 18.08.2020)

CPU load unchanged…

Probably because I haven’t had the chance to investigate yet, been back from vacation only for 4 (work) days.

I have related question, what are the requirementes to have the denoiser feature?
I don’t have it, I have a quadro P2000 and a not so new I7 processor.

When in doubt the Intel denoiser is the safest bet - it is CPU-only, and will work on both Intel and AMD CPUs.

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Ahh sorry, I only wanted to make sure it gets attention…

This appears to be related to the usage of OpenMP in a certain bit of code. This code wasn’t used in v6, but is now in v7. We’ll investigate more and hopefully come up with a workable fix.

I have logged a bug with my findings as RH-60016

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I’m confused about this thread. We are rendering - ideally you’d like things to go faster, right? We have processor cores sitting there unused in v6 - and now we are using them in V7…what’s the problem?

  • Andy

For my sake this is all about when Cycles (Raytraced view) is done rendering and at IDLE. And even if we toggle to rendered mode Raytraced seems to use the cpu. (See the data in my post above) and just using the CPU when not needed to is never desired. On a laptop that means more noice (warmer cpu) and shorter batterylife + slower cpu as they tend to trottle down when hot.


I believe that part of the bug has been fixed.
_ Andy

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Regarding RH-60016 the problem is that the CPU utilization doesn’t match the gained benefit, most of the CPU cycles are actually lost to overhead (thread managementy stuff) instead of doing anything useful (copying pixel data). This is when Raytraced is otherwise rendering on the GPU.

I guess that part should be split off from this thread.


Yup - that part I understand…but let’s say I make things go 100% faster, but instead of using 20% of CPU, I’m using 100%…will people be happy or sad?

I don’t see faster rendering in V7…

Using the whole CPU is not good, as we can’t do anything useful on the PC when a single Rhino instance eats all the power.
We select CUDA, and not CPU for reasons.