How are ticks skipped during long processing?

Good afternoon,
Let’s say my expert Advisor in OnTick performs some long processing that lasts 3 ticks. How the terminal will behave:
1. OnTick will be called in a separate process while the previous tick is being processed2. These 3 ticks will be skipped. If so, what will I see in the next ontick call: the current state or the state on the second tick after the tick with long processing?