[ovs-discuss] Early addition of flows in the kernel.

[Jesse Gross]

On Mon, Oct 12, 2015 at 5:17 AM, jimson chacko
<jimsonchacko at gmail.com> wrote> Hi,
>
> As per my understanding, OVS inserts the flow in the kernel when an
> exception packet is handled by the vswitchd (ofcourse when matching flow is
> present in the vswitchd).
>
> Is it possible to push the flow into the kernel as soon as the flow gets
> added to vswitchd ? This enables in avoiding the exception mechanism and
> hence faster processing.

No.

> Can you briefly let me know why the design was kept so ?

It's not possible to do in a general and efficient manner. The flows
kept by the kernel are significantly simpler than the ones in
userspace to make them easier to process. The consequence is that they
are less expressive and you can potentially need a lot more of them to
cover the entire space, which is prohibitively expensive.