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NVIDIAGameWorks / RTX-Path-Tracing

Real-time path tracing library and sample
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Enable SER cause performance drop. #4

Closed edisonchan closed 1 year ago

edisonchan commented 1 year ago

Scene: timemachnine GPU: RTX 6000 Ada w/531.18 on windows 11 pro, 3840x2160 120Hz.

enable SER(default setting): 17.4 fps(slow down from about 18fps) disable SER: about 20fps.

fstrugar-nv commented 1 year ago

Hi! Thanks for the report - yeah, 'Transparent Machines' is a glass jaw use case for SER where the whole scene is basically single material, single model, no textures, etc. In this case there is no branch or data divergence and sorting provides no benefit so what you see is the sorting overhead.

There is however an unrelated change planned that should reduce this overhead, so I will leave this issue open until that task is done!

fstrugar-nv commented 1 year ago

Update on this: SER should cause a lot less performance drop in v1.1.0 - it's disabled in the non-stochastic pre-pass where it was almost always causing more overhead than benefit.

There will still be rare scenarios where SER overhead slightly outweighs the benefits, but that is expected.