[Open vSwitch] How to get port statistics from interface in OVS

1. Show the bridge info
> sudo ovs-vsctl show
result:
2909bfce-536e-4184-a5bb-507f0553abee
    Bridge "br0"
        Controller "tcp:10.6.186.244"
        Port "br0"
            Interface "br0"
                type: internal
        Port "eth3"
            Interface "eth3"
        Port "eth2"
            Interface "eth2"
        Port "eth1"

2. Get port statistics from interface
> sudo ovs-vsctl get Interface br0 statistics
result:

{collisions=0,

rx_bytes=0,

rx_crc_err=0,

rx_dropped=0,

rx_errors=0,

rx_frame_err=0,

rx_over_err=0,

rx_packets=0,

tx_bytes=0,

tx_dropped=0,

tx_errors=0,

tx_packets=0}