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> Raytracing is a not a problem that is well suited to GPUs since there are lots of data dependencies, which means parallelism is severely limited. This is a j
by tomxor 7y ago
> Raytracing is a not a problem that is well suited to GPUs since there are lots of data dependencies, which means parallelism is severely limited.
This is a joke right? I mean ray tracing is the most common example pointed at as being highly amenable to parallel computation. all ray computations are independent (i.e cores), all scene and BDRF data are shared - this matches GPU architecture perfectly, the only reason it's more of a recent trend is because even with parallel compute it's still demanding for real time performance.
If you don't believe me you can go to shadertoy right now and see endless demos doing raycasting and pathtracing in a quad.
- 0-_-0 7y agoRaytracing is indeed ill suited to GPUs because of the terrible cache coherency you get in a real scene that has a size measured in gigabytes instead of kilobytes that scenes on Shadertoy take up.
- kllrnohj 7y ago> all ray computations are independent (i.e cores) Which makes it ill-suited to GPUs since they want sibling threads to take the same execution path on cache coherent data. Better than a quad core CPU sure but a very small fraction of the performance they're otherwise capable of. You can see this with the DXR performance on Pascal vs. Turing.