This patch adds two new kernels: SORT_BUCKET_PASS and SORT_WRITE_PASS. These replace PREFIX_SUM and SORTED_PATHS_ARRAY on supported devices (currently implemented on Metal, but will be trivial to enable on the other backends). The new kernels exploit sort partitioning (see D15331) by sorting each partition separately using local atomics. This can give an overall render speedup of 2-3% depending on architecture. As before, we fall back to the original non-partitioned sorting when the shader count is "too high".
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D16909
This was added for Metal, but also gives good results with CUDA and OptiX.
Also enable it for future Apple GPUs instead of only M1 and M2, since this has
been shown to help across multiple GPUs so the better bet seems to enable
rather than disable it.
Also moves some of the logic outside of the Metal device code, and always
enables the code in the kernel since other devices don't do dynamic compile.
Time per sample with OptiX + RTX A6000:
new old
barbershop_interior 0.0730s 0.0727s
bmw27 0.0047s 0.0053s
classroom 0.0428s 0.0464s
fishy_cat 0.0102s 0.0108s
junkshop 0.0366s 0.0395s
koro 0.0567s 0.0578s
monster 0.0206s 0.0223s
pabellon 0.0158s 0.0174s
sponza 0.0088s 0.0100s
spring 0.1267s 0.1280s
victor 0.0524s 0.0531s
wdas_cloud 0.0817s 0.0816s
Ref D15331, T87836
This patch partitions the active indices into chunks prior to sorting by material in order to tradeoff some material coherence for better locality. On Apple Silicon GPUs (particularly higher end M1-family GPUs), we observe overall render time speedups of up to 15%. The partitioning is implemented by repeating the range of `shader_sort_key` for each partition, and encoding a "locator" key which distributes the indices into sorted chunks.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D15331
* Replace license text in headers with SPDX identifiers.
* Remove specific license info from outdated readme.txt, instead leave details
to the source files.
* Add list of SPDX license identifiers used, and corresponding license texts.
* Update copyright dates while we're at it.
Ref D14069, T95597
Remove prefix of filenames that is the same as the folder name. This used
to help when #includes were using individual files, but now they are always
relative to the cycles root directory and so the prefixes are redundant.
For patches and branches, git merge and rebase should be able to detect the
renames and move over code to the right file.
