Blender Git Loki

Merge branch 'master' into tmp-task-foreach-pool

Add threaded handling of finalize callbacks for parallel range pool.

As suggested by @sergey in review comments, thanks.

Thhis will add a additional speed-up benefit to using those pools when
finalization computations are not trivial.

Merge branch 'master' into tmp-task-foreach-pool

More naming consistancy cleanup + fix bug in single thread case with tls data.

Merge branch 'master' into tmp-task-foreach-pool

Updates from review (var naming mostly).

Merge branch 'master' into tmp-task-foreach-pool

Merge branch 'master' into tmp-task-foreach-pool

Pool range iter: compute 'static' scheduler chunk size from smallest range.

Computing it from sum of all the ranges is rather stupid and meaning
less, pooled range iterator needs to be at least somewhat dynamic in any
case...

Merge branch 'master' into tmp-task-foreach-pool

BLI_task: Initial implementation of pooled threaded index range iterator.

This code allows to push a set of different operations all based on
iterations over a range of indices, and then process them all at once
over multiple threads.

This is mainly interesting for relatively low amount of individual
tasks, as expected.

E.g. performance tests on a 32 threads machine, for a set of 10
different tasks, shows following improvements when using pooled version
instead of ten sequential calls to `BLI_task_parallel_range()`:

| Num Items | Sequential | Pooled | Speed-up |
| --------- | ---------- | ------- | -------- |
| 10K | 365 us | 138 us | 2.5 x |
| 100K | 877 us | 530 us | 1.66 x |
| 1000K | 5521 us | 4625 us | 1.25 x |

Differential Revision: https://developer.blender.org/D6189