Multithreading options

[ateixeira0163]

Hi there!
I'm currently using the plugin Multithreading from SOFA and I made some changes in my script to put these objects in my scene:
Added AnimationLoopParallelScheduler to the root with threadNumber=0. (I kept FreeMotionAnimationLoop for the friction contact constraint).
Changed the multithreading=True in the GenericConstraintSolver
Changed BruteForceBroadPhase to ParallelBruteForceBroadPhase
Changed BVHNarrowPhase to ParallelBVHNarrowPhase
Changed HexahedronFEMForceField to ParallelHexahedronFEMForceField
And still, after those changes, an example simulation that took 19h22m with a single thread took 19h12 with multithreading. Is it normal that the difference is so low (I made sure that there was nothing else in the computer and the computer has 8 threads total).

Thanks for all information possible :)
Ps.: @hugtalbot asked me to tag you @alxbilger

[alxbilger]

Hi,

if I understand correctly, your goal is not to use the MultiThreading plugin, but to speed up your simulation. In that case, I suggest you to read this doc page: https://github.com/sofa-framework/doc/blob/master/15_Using_SOFA/32_Performances/20_Improve_performances.md. The most important thing is to identify the bottleneck. Otherwise, we won't be able to help. For example, you use ParallelBruteForceBroadPhase, but if you have collision only between two objects, it is counter-productive.

The multithreading plugin is not very used, and not a lot of effort has been made to optimize it. Consider it experimental, without any guarantee of improving the performances. Still, I encourage you to read the documentation: https://github.com/sofa-framework/doc/blob/master/35_Plugins/50_Usual_plugins/80_MultiThreading.md. In particular, using ParallelHexahedronFEMForceField speeds up the simulation only in specific cases.

Again, identifying the bottleneck is the key.

Alex

[ateixeira0163]

I only have one object with self-contact.
Thanks! I'm gonna read to optimize my simulation!