A method for determining a packet dequeue rate includes allocating a plurality of consecutive blocks in a first memory to a first packet, storing the first packet and a first length in the plurality of blocks, where the first length is of a first packet queue and is obtained when the first packet is enqueued into the first packet queue, and determining, based on a first span and the first length stored, a first rate at which a packet in the first packet queue is dequeued, where the first span is equal to a difference between a second time and a first time, the first time is when the first packet is enqueued into the first packet queue, and the second time is when the first packet is dequeued from the first packet queue.