Optix 3.9.1 vs 5.0.0 pathtracer samples performance

Gaming and Visualization Technologies Visualization OptiX
1

Hi

I’m having trouble figuring out why there is a big performance difference at startup of the Optix 3.9.1 sample projects compared to 5.0.0.

In my tests the difference is big, in the pathtracer example using 3.9.1 runs in 2 seconds, in 5.0.0 runs in 22 seconds.

Any reason for this difference?

My system
Windows 10
NVidia GPU 650M
Dirver 385.54

2

I’m unable to reproduce this on my current development configuration (Quadro P6000, Win10-64 1607, 397.64 drivers) with the precompiled SDK examples.
Either the OptiX 3.9.1 path_tracer.exe, the OptiX 5.0.0 optixPathTracer.exe, or the current OptiX 5.1.0 optixPathTracer.exe starts in under 2 seconds.

Have you by chance enabled OptiX exceptions inside the slower application?
At OptiX 4 the internal kernel compiler was completely rewritten to use LLVM and that will take a lot longer when generating the code for the exception handling than in previous versions.

That said, when switching to an OptiX 5 version, please note that OptiX 5.1.0 has just been released last week and that also contains changes to improve startup times in general.

Also the optixPathTracer inside the SDK is a very limited example. For some more elaborate path tracer implementation have a look at the sticky post in this sub-forum explaining the new additions to the OptiX Advanced Samples on github.

3

Hi Detlef.

I did other tests without debug and in fact the problem is there. I will try apply the upgrade to 5.1.0 in my renderer and see what happens.

Thank’s

Note: The AI Denoiser is amazing, I’d really like to know how the algorithm works because I built a denoiser using bilaterial filtering on separated maps (DL, IL, Reflection, Refraction) and got really good results, but not comparable in performance

4

You can find a lot more information on Deep Learning Denoisers here: [url]https://developer.nvidia.com/optix-denoiser[/url]

There’s also at least one Deep Learning Institute course about that here: [url]https://developer.nvidia.com/dli/onlinelabs[/url]

I’ve just pushed a new OptiX Introduction example to the OptiX Advanced Samples github repository which shows how to the use the new HDR DL Denoiser in OptiX 5.1.0.