Thanks! The idea of having a list of migrating entities per chunk is good, and it avoids locking on the list of all entities in a chunk. But I still have some confusion about it:
> The server looks up the destination in the "active chunk set" I mentioned
but what if the entity teleports to an inactive chunk?
> and then uses per-chunk std::vectors guarded by a mutex to push "migrating" entities.
Will these migrating entities participate in later calculation within the same tick, or are they excluded? If excluded, what happens when there are two mechanisms that mutates that entity, but the first one put it into the migrating list of another chunk? If included, the thread of which chunk will continue this calculation?
And when some kind of mechanism mutates two entities in different chunks, which thread is chosen to run this mutation? And how does it mutate the state for an entity in the other chunk?
Meanwhile since you mentioned ticks, (just to be sure) are you using a barrier per tick to wait for all threads to finish the same tick? When are the migrating entities merged into the main list, and are you using another barrier for that?