GPU Rendering and cpu % utilization 100% ?

[GVANDERV]

Hi,

I am pretty novice with vray rt. I have a I7-5930k, one quadro K4000 for viewport and two GTX 760 for RT. Whenever I start a RT rendering it uses 100% of the cpu as well until it finishes. Is this normal ? If not anyone has any idea ?

I am using vray on rhino 5.

thank you.

[Alan Iglesias]

Not too familiar with Rhino, but if you are new to RT is there a chance that you might have not switched the RT engine from CPU to Cuda to use the GPUs?

Just a guess...

-Alan

Edit: Just noticed you said "as well'...so both the GPUs and CPUs are at 100%?

[3LP]

Yeah that's weird, it shouldn't.
My CPU is working at 10-20 % to handle my 3x970s, definitely not 100%.

You didn't do the 4 years old trick where it was possible to run opencl on cpu in conjunction with RT GPU opencl through a environment variable.
I know it's kind of a stretch but it's the only thing that could make me think you're utilizing 100% of cpu.
Beside being rendering in cpu as Alan said but I guess that's not it.

Stan

[GVANDERV]

I forgot to mention I have the educational version of Vray 2.0

I know it is weird. I do not think it was doing this a first. When I look at the cpu ressource it is at 60% in opencl and the two GTX are at between 90% and 100% all the time. When in CUDA mode its worst, cpu is between 60% and 100%. Its really strange. And yes i am sure that it is in cuda mode. Only the two GTX are chosen in the opencl choose devices.

What is weirder is that when I choose the 3 graphics cards in the opencl menu before launchin vray. It now oscilate between 10 to 25% of cpu usage. Than all the graphics in the nvidia gpu utilization shows 90% of usage.

[GVANDERV]

Alan,

yes the as well ment cpu and gtx. I am not even able to reproduce that 10% cpu anymore even when choosing the 3 video cards. Whenevenr I rotate the view, it goes at 100% cpu, 100% gpu (à to be exact it oscilate between 60 to 90% gpu) and the cpu goes down to 50% 60% after 10 sec of the view rotation. sorry if my english is not that clear.

[3LP]

I can't comment on the educ version of Vray 2 but if you'd like, I can spin it up on my Vray 3 and see how it goes.
At least you'd know if it's scene or vray version related.
Just MP me with the link if you'd like that.

Cheers
Stan

[GVANDERV]

I tried with a simple scene (a bed from flyingarchitecture) and still the RT uses between 70 and 90% cpu and between 60 to 90% gpu.

[Alan Iglesias]

Alan,

yes the as well ment cpu and gtx. I am not even able to reproduce that 10% cpu anymore even when choosing the 3 video cards. Whenevenr I rotate the view, it goes at 100% cpu, 100% gpu (à to be exact it oscilate between 60 to 90% gpu) and the cpu goes down to 50% 60% after 10 sec of the view rotation. sorry if my english is not that clear.

Your English is fine. I'm sorry I couldn't help...

-Alan

[Svetlozar Draganov]

I tried with a simple scene (a bed from flyingarchitecture) and still the RT uses between 70 and 90% cpu and between 60 to 90% gpu.

Would it be possible to send us that scene to support@chaosgroup.com for investigation?
If the scene is too large to be sent via email we could provide our FTP server - just let us know on the same email address.

[GVANDERV]

Yes of course. The rhino scene is 112 mb though. I will send it with the vray preset. But as I mentionned before, this problem also occurs with other scene.

Thanks.

[Svetlozar Draganov]

The issue might be caused by the same thing used in all scenes, it is worth to investigate at least one of them.
I've already did a couple of tests on a few random scenes but the CPU usage was 100% only at the beginning of the rendering then it dropped to 15%.

[GVANDERV]

Could you send me the same scene you have tried so we could also know if its my computer / driver or whatever. and the vray preset. You have tried it on the educational version 2.0 ?

Thanks

[Svetlozar Draganov]

Could you send me the same scene you have tried so we could also know if its my computer / driver or whatever. and the vray preset. You have tried it on the educational version 2.0 ?

Thanks

Please go to the link bellow and download the scene from point 1.1:
http://docs.chaosgroup.com/display/V...Interior+Scene

This scene utilize the CPU at 100% at the beginning of the rendering or when changing something in the scene.
Let us know the result from the tests in your environment.

[GVANDERV]

In cuda mode: GTX @ average of 95 to 97% / CPU average 95 to 100%
Open CL mode: GTX @ average of 95 to 97% / CPU average 65 to 85%

Ran it 5 minutes each test.

[Svetlozar Draganov]

Thank you very much for the feedback.
V-Ray RT most likely fail to render the image with OpenCL and CUDA engines and it automatically switches to CPU engine - that's why the CPU utilization is so high.
Would you please let us know what is the GPU utilization during the rendering?
When open OpenCL Device select tool - are you able to see all the GPU devices installed on the machine? Can you show us a screen-shot from it?

We will also need to investigate the log file from the rendering.
In order to get that log please open Task Manager and Stop XMLDRSpawner.exe process if it is already started:

Then run Launch Distributed Rendering Spawner from Start Menu > Chaos Group > V-Ray for Rhino > Distributed Rendering folder:

Then run V-Ray RT CUDA rendering, leave it to render for a minute then right click on the black DR-spawner window Edit > Select All to select all text, paste it into a new text document and send it to us for investigation:


We are looking forward to hearing from you.