Ray Sorting back

(L) [2015/02/05] [ost by fluid] [Ray Sorting] Wayback!

Hi guys,
Anybody has some experience with ray sorting on CPU based path tracers?
I'm working on a CPU-only path tracer/bidirectional path tracer based on Embree. I was thinking about implementing ray reordering and packet tracing for incoherent rays to increase performance (since Embree supports packet tracing).
I was wondering what kind of performance improvement is to be expected (if any). Would you suggest any papers on the subject?
Thanks,

   Nicola

(L) [2015/02/07] [ost by raider] [Ray Sorting] Wayback!

For out of core scenes performance improvement can be quite significant. Have a look here [LINK https://disney-animation.s3.amazonaws.com/uploads/production/publication_asset/70/asset/Sorted_Deferred_Shading_For_Production_Path_Tracing.pdf]

(L) [2015/02/09] [ost by fluid] [Ray Sorting] Wayback!

It seems to make sense for out of core rendering, it's not clear if, for cases where everything fits in memory, increased cache coherence would still increase performance in a sensible way.

(L) [2015/02/10] [ost by koiava] [Ray Sorting] Wayback!

fluid
Shading part is very important because every shading event may be linked to some textures(diffuse, specular, normal, displace) and in productions renderers this number and size of textures may be very large. So processing shading events in coherently useful way really important.
Your question is more about ray traversal optimizations. There is [LINK http://research.microsoft.com/en-us/um/people/cloop/garanzhaloop2010.pdf some techniques] which groups incoherent rays in coherent ray groups using hash function.
In general this techniques is more important in Out of Core renderers.

(L) [2015/02/10] [ost by fluid] [Ray Sorting] Wayback!

Hi Koiava,
Thanks for the link. I was trying to figure out if re-writing code using ray sorting is worth the effort in the case of everything fitting in main memory.
For out of core rendering, it seems to be the case.