：DMA数量增加（不过一个是1520个字节啊，真大）。提高收发处理速度，没仔细看过内核，假如收发线程优先级较低，根据优先级来说，假如优先级较高的线程在运行，应该还有较大延迟-: DMA increased (but one is 1520 bytes, ah, really big). Improve processing speed transceiver, not carefully read the kernel, if the sending and receiving a lower priority thread, according to priority, the higher priority thread if the running, there should be a greater delay