Not enough GPU memory sometimes, but there is enough memory (nightly build)

[Micha]

I use two 2080ti for rendering and one 1080ti for display only. Some times today the rendering doesn't started because there is not enough memory. But the memory was ok. If I close Rhino and start again, than it works and the GPU shows an usage of 4,4GB. Looks like the memory approximation doesn't work right.


I hope the screenshot helps.

[Micha]

Today I tried one of my project files from the past. I got that not enough memory is available.If I get it started than it crash during the GPU BF pass.

Maybe interesting is this line from the progress window:
--------------------

Switching kernels after reaching 64 samples per pixel...

Num samples per thread reduced to 362031, rendering might be slower

Num samples per thread reduced to 362031, rendering might be slower

Failed to allocate 671929536 bytes, device 1, buffer default bufname

Failed to allocate 671929536 bytes, device 1, buffer default bufname

D:\cgrepo\vraysdk\samples\vray_plugins\rt_private\ rt_opencl_pri(3623) : CUDA error 2 : unable to allocate enough memory to perform the requested operation (out-of-mem)

Failed to allocate 671929536 bytes, device 1, buffer default bufname

Failed to allocate 671929536 bytes, device 1, buffer default bufname

Closing RTEngine (cancelled)

Max. Mpaths per second: 0.000000

Sampling level reached: 64 samples per pixel

V-Ray GPU kernel render time: 36.72s

Total GPU samples 170398208

Mtls 921.65MB, Geo 1024.72MB, Lights 17592186044416.00MB, LightCache 13.22MB,

-----------------

If I render the scene per last official version than it looks so:

---------------
GPU adaptive lights v2 built successfully Closing RTEngine (cancelled)
Max. Mpaths per second: 6.120407
Sampling level reached: 64 samples per pixel
V-Ray GPU kernel render time: 125.23s
Total GPU samples 730979456
Mtls 926.43MB, Geo 1023.87MB, Lights 2746.59MB, LightCache 12.76MB, Reserved 2869.52MB
------------

It looks like it is something wrong with the lights and the memory usage.

[Peter.Chaushev]

Thank you for reporting this!

Lights 17592186044416.00MB

This calculated amount seems impossible indeed. Could you please share the scene with us for investigation?

Kind regards,
Peter

[Micha]

I send it to the Support and it got the ticket 269-408-8326 

It's a project scene and I hope it help to find some other issues too. More details in the email.

Good luck.

[Peter.Chaushev]

Thank you! Scheduled it for investigation. Will be able to give you an update on Monday (March 2nd).

Regards,
Peter

[Peter.Chaushev]

Just want to let you know a bit more time will be needed to be able to provide you with a safe workaround to your issue. Will give you an update as soon as possible.

Kind regards,
Peter