Unity Game Optimization - Third Edition

Garbage collection at runtime

So, in a worst-case scenario, when a new memory allocation is being requested by our game, the CPU would have to spend cycles completing the following tasks before the allocation is finally completed:

1. Verify that there is enough contiguous space for the new object.
2. If there is not enough space, iterate through all known direct and indirect references, marking everything they connect to as reachable
3. Iterate through all of these references again, flagging unmarked objects for deallocation
4. Iterate through all flagged objects to check whether deallocating some of them would create enough contiguous space for the new object
5. If not, request a new memory block from the OS to expand the heap
6. Allocate the new object ...