Blender Git Commit Log

Git Commits -> Revision 6238214

Revision 6238214 by Mai Lavelle (master)
June 10, 2017, 08:08 (GMT)
Cycles: Faster split branched path tracing by sharing samples with inactive threads

Unlike regular path tracing, branched path tracing is usually used with lower
sample counts, at least for primary rays. This means that are less samples for
the GPU to work on in parallel and rendering is slower. As there is less work
overall there is also more inactive threads during rendering with BPT. This
patch makes use of those inactive rays to render branched samples in parallel
with other samples.

Each thread that is preparing for a branched sample will attempt to find an
inactive thread and if one is found the state for the sample is copied to that
thread. Potentially, if there are enough inactive threads, 100s of branched
samples could be generated from the same originating thread and ran in
parallel giving large speed ups.

Gives 70% faster render for pavillion midday scene. 20-60% faster on BMW
with car paint replaced with SSS/volumes.

Commit Details:

Full Hash: 6238214159a4229ded91cd36d14c8e55ff427c28
Parent Commit: 32299d3
Lines Changed: +142, -5

10 Modified Paths:

/intern/cycles/device/device_split_kernel.cpp (+1, -0) (Diff)
/intern/cycles/kernel/kernel_types.h (+3, -0) (Diff)
/intern/cycles/kernel/split/kernel_branched.h (+51, -1) (Diff)
/intern/cycles/kernel/split/kernel_do_volume.h (+19, -0) (Diff)
/intern/cycles/kernel/split/kernel_next_iteration_setup.h (+2, -0) (Diff)
/intern/cycles/kernel/split/kernel_scene_intersect.h (+13, -3) (Diff)
/intern/cycles/kernel/split/kernel_shadow_blocked_dl.h (+8, -0) (Diff)
/intern/cycles/kernel/split/kernel_split_common.h (+14, -1) (Diff)
/intern/cycles/kernel/split/kernel_split_data_types.h (+23, -0) (Diff)
/intern/cycles/kernel/split/kernel_subsurface_scatter.h (+8, -0) (Diff)
By: Miika HämäläinenLast update: Nov-07-2014 14:18MiikaHweb | 2003-2021