[Bf-cycles] Cycles CPU speedup: Perlin noise

[storm]

В Пт, 27/12/2013 в 20:58 +0100, Thomas Dinges пишет:
> Hi everyone,
> today Svyatoslav Lockal send us a great patch which improves Perlin 
> Noise calculation for Cycles CPU rendering, it's in master now.
> https://developer.blender.org/rBa92abf5089e152d8d1b1fd95278b307f56b6a193
> 
> Some tests with the BMW scene resulted in a 12-15% render speedup.
> 
> But I was curious to see how this behaves in a more production like 
> environment, so I checked a file from the Open Movie Caminandes.
> The scene I used was 11a_comp.blend (New Hope scene) from Caminandes on 
> an Ivy Bridge Quad Core (3.4 GHZ) on Linux.
> I rendered frame 500, with 1280x720 resolution, otherwise it's unmodified.
> 
> http://www.pasteall.org/pic/show.php?id=64561
> 
> Before: 01:06:22h
> New: 53:13min
> 
> That is a speedup of about 20% (19.76%), which is a lot. I checked the 
> node setups and the artists used the Noise Texture almost everywhere. :D
> 
> Just wanted to share this, enjoy!
> 
> Best regards,
> Thomas
> 
> 
> 
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Great patch. In fact, I see perlin noise taking 90% of CPU time in
volume scenes with variable density (tat expected obviously, as woodcock
delta tracker or ray marsher call it evey small step while traversing
ray).