如果guest虚拟机也正在运行Linux，或者它们在主机上具有单独的接口，则可以使用/sys/class/net/$ interface_name/statistics/rx_bytes和tx_bytes，只需比较差异并除以时间即可得出当前吞吐量的估算值.

If the guests are also running Linux or they have separate interfaces on the host, you can cat /sys/class/net/$interface_name/statistics/rx_bytes and tx_bytes, just compare the difference and divide by time to get an estimate of current throughput.