Queue size is not important. The time a request resides in the queue is. If you have short burst, the queue will fill quickly and drain quickly, and a request w

Queue size is not important. The time a request resides in the queue is. If you have short burst, the queue will fill quickly and drain quickly, and a request will only stay a short time in it. If your system is overloaded, the requests' 'sojourn time' will increase and stay high. Google for papers about codel/controlled delay. In any case, backpressure and discarding requests (just another form of backpressure) only move the queue upstream towards the sender. One strategy to deal with this is only to backpressure requests of a subset of users. Only they will experience high delay.