[ovs-discuss] Does the OpenFlow userspace execute sequentially?

[Jesse Gross]

On Fri, Nov 8, 2013 at 6:24 AM, Xiaoye Sun <Xiaoye.Sun at rice.edu> wrote:
> I am wondering if there is a race condition between the flow-mod and the
> incoming packet.
>
> When ovs userspace receives a flow-mod message from a remote controller,
> does it has higher priority over processing incoming packets (kernel
> upcalls) or this flow-mod message and the flow miss upcalls are processed
> concurrently?

There's no interlocking of flow table modifications and packet
processing. It wouldn't make sense to do so in the switch since
nothing else provides those guarantees.