[Controller] POC: overall speedup

[fredroy]

I did detect this issue some time ago, about having a controller in a scene was slowing down the simulation so much, especially on macOS. Even if the controller do nothing. And it gets slower and slower more there are Controllers.

DISCLAIMER: this was mostly the work of Claude, which detected/suggested the issues (lookups were slowing down the simulation) and generated the solution.
I just did the benches/tests to make sure it works, but as for everything with sofapython3 and/or pybind11, I cannot prove everything is okay/well-done. So deep review from experts would be appreciated 🫠

In any case, the modifications lead to a dramatic speed up:
(refer to the scene with this PR, which creates an empy scene with a certain number of Controller doing nothing)

Ubuntu 22.04 (gcc12, i7 13700k)

before:
Scene with 1 controllers and 10000 steps took 2.464146852493286 seconds.
Scene with 5 controllers and 10000 steps took 12.076464414596558 seconds.
Scene with 10 controllers and 10000 steps took 24.062500715255737 seconds.

after:
Scene with 1 controllers and 10000 steps took 0.04976940155029297 seconds.
Scene with 5 controllers and 10000 steps took 0.09446001052856445 seconds.
Scene with 10 controllers and 10000 steps took 0.1459205150604248 seconds.

--> with 10controllers, 150x faster... 😮

Windows (MSVC2026, i7 11800h)

before:
Scene with 1 controllers and 10000 steps took 6.102800607681274 seconds.
Scene with 5 controllers and 10000 steps took 27.300215482711792 seconds.
Scene with 10 controllers and 10000 steps took 54.59787082672119 seconds.
after:
Scene with 1 controllers and 10000 steps took 0.12163424491882324 seconds.
Scene with 5 controllers and 10000 steps took 0.18189406394958496 seconds.
Scene with 10 controllers and 10000 steps took 0.27340126037597656 seconds.

--> with 10controllers, 200x faster... 😲

macOS (xcode26, M3 max)

before:
Scene with 1 controllers and 10000 steps took 8.079632759094238 seconds.
Scene with 5 controllers and 10000 steps took 40.43093395233154 seconds.
Scene with 10 controllers and 10000 steps took 79.13048505783081 seconds.

after:
Scene with 1 controllers and 10000 steps took 0.03541707992553711 seconds.
Scene with 5 controllers and 10000 steps took 0.06284904479980469 seconds.
Scene with 10 controllers and 10000 steps took 0.09451079368591309 seconds.

--> with 10controllers, 837x faster... 🤪

[alxbilger]

Is the cache system also relevant for other trampoline classes?

[fredroy]

Is the cache system also relevant for other trampoline classes?

To my meager knowledge, I would say yes. But in this case it is especially useful because there were(are) many lookups to call implicitly all the *event() every step.

[bakpaul]

Nice cache mechanism. Now I wonder what would happend if someone changed dynamically the method after it has already been cached :

MyController.onAnimateBeginEvent() # Cache is now active for this method
MyController.onAnimateBeginEvent = randomMethod # Cache is now invalid
MyController.onAnimateBeginEvent() # now what's called ? 

Maybe we could add a setattr overloead invalidating the cache when it is called on a method already cached ?

[fredroy]

Nice cache mechanism. Now I wonder what would happend if someone changed dynamically the method after it has already been cached :

MyController.onAnimateBeginEvent() # Cache is now active for this method
MyController.onAnimateBeginEvent = randomMethod # Cache is now invalid
MyController.onAnimateBeginEvent() # now what's called ? 

Maybe we could add a setattr overloead invalidating the cache when it is called on a method already cached ?

no idea, I even did know you could change class method dynamically like that 🙃