Physics generating unexpected garbage.

I would never expect garbage generated from OverlapBoxNonAlloc, the name itself implies it, however It generates 120 bytes of garbage.



Another feature that generates garbage but shouldn't is RaycastHit.collider, as you can see below.



The garbage is generated by a call to FindObjectFromInstanceID. For some reason this last function sometimes, not always generates 40 bytes of garbage.

 

Which Unity version?

 

Do not profile in the editor. The editor comes with overhead. For example GetComponent calls that don't return any Component, normally allocate a ton of garbage in the editor, which is completely gone in a build. There are various other cases where this is true in the editor.

Profiling the game running in the editor is quite inaccurate, profile a build on the target hardware instead.

That being said, I don't remember having seen FindObjectFromInstanceID ever. If that method is new, there is a chance that it's creating garbage memory. However, I still recommend to check that in a build as well.

 

Do you have a case number you can drop in the thread so friendly curious staff take a peep?

 

A simple GetComponent may generate garbage in editor but not in build (apparently it's because it creates some internal debug string warnings if the component was not found, etc....)

It's very possible that in this case, OverlapBoxNonAlloc tries to do some GetComponents internally too

 

2018.1.0b13

 

I'm not seeing it every frame, is more like once every second or two, and not at a regular intervals, but certainly more than once.

 

No, on the player build I'm not getting any garbage as fas as I could test, so I guess is a false alarm.