Openvswitch Qos question

I install openvswitch in my WNDR4300.But I found the ingress policing qos function of openvswitch dosen't work. Why?

I try:
ovs-vsctl set interface eth1 ingress_policing_rate=1000

It dosen't work,the speed of eth1 dosen't change.

However,when I try:
ovs-vsctl set port eth1 qos=@newqos --
--id=@newqos create qos type=linux-htb queues=0=@q0 --
--id=@q0 create queue other-config:max-rate=1000000 other-config:min-rate=1000000
I works.(the speed changes obviously)

How to explain why the ingress policing of Qos function can't work only?

Does anyone know this question?

If this question is not specific to OpenWrt, you will probably get more information on the openvswitch forums.