Previously this would be enabled when threads were used, but threads are now
basically always in use so there is no point. Further, this is only needed for
guarded allocation with --debug-memory which is not performance critical.
In some cases blender could freeze. When threads are blocked (waiting for other tasks completion) the scheduler can let the thread perform a different task. If this task wants a write-lock for something that was read-locked in the stack a dead lock will happen.
For task pools every task is isolated. For range tasks the inner loop will be isolated. The implementation is limited as isolation in TBB uses functors which are tricky to add to a C API. We decided to start with a simple and adapt were we need to.
During testing we came to this setup as it was reliable (we weren't able to let it freeze or crash) and didn't had noticeable performance impact.
Reviewed By: Brecht van Lommel
Differential Revision: https://developer.blender.org/D7688
This patch enables TBB as the default task scheduler. TBB stands for Threading Building Blocks and is developed by Intel. The library contains several threading patters. This patch maps blenders BLI_task_* function to their counterpart. After this patch we can add more patterns. A promising one is TBB:graph that can be used for depsgraph, draw manager and compositor.
Performance changes depends on the actual hardware. It was tested on different hardwares from laptops to workstations and we didn't detected any downgrade of the performance.
* Linux Xeon E5-2699 v4 got FPS boost from 12 to 17 using Spring's 04_010_A.anim.blend.
* AMD Ryzen Threadripper 2990WX 32-Core Animation playback goes from 9.5-10.5 FPS to 13.0-14.0 FPS on Agent 327 , 10_03_B.anim.blend.
Reviewed By: brecht, sergey
Differential Revision: https://developer.blender.org/D7475
