[ovs-discuss] bug: Adding or deleting port results to flush of QoS policy for all bridge ports

[Ben Pfaff]

On Fri, Jul 25, 2014 at 07:29:24PM +0400, Andrey Korolyov wrote:
> Assuming we have trivial case: libvirt, its QoS limits (for which
> appropriate rules are executed for each port) and more than one VM
> sharing the same OVS bridge. Port configurations are initially empty
> and addition going through libvirt` internal command execution by
> calling ovs-vsctl binary, so no QoS configuration is performed through
> existing vswitchd mechanisms.
> 
> Since OVS decides to flush all disciplines every time when port added
> or removed from the switch, one will not be able to keep more than one
> port with externally set tc disciplines.
> 
> At least this bug affects 0fe1d7f39de9836fea01c560a6fdbfd1405096ea
> (2.1.3 effectively) in Openflow mode, though probably cover area is
> wider. FAQ suggests tc as a fallback method for complex
> configurations, so I can guess that the bug is definitely a bug but
> not an expected behavior.

It does sound like a bug.  Do you have time to fix it?