Re: [PATCH 4/4] rps: Inspect GRE encapsulated packets to get flow hash

[Tom Herbert <therbert@google.com>]

Eric,

Thanks for comments.

> For sure it helps if this machine is the final host for these packets.
>
I would hope it helps routers too, assuming RPS already helps non
encapsulated traffic in a router.

> If I am a firewall or router [and not looking into GRE packets], maybe I
> dont want to spread all packets received on a tunnel to several cpus and
> reorder them when forwarded.
>
Do know a specific use case where this patch would be a bad thing?  I
don't believe there's any special ooo constraints on the packets in a
tunnel, flow ordering should still be maintained.

> 3) table could contains 'pointers' to decoding function, that would
> recompute a new rxhash function.
>
This could be done as a function in the protocol switch table, so that
all the protocol specific code could be moved out of dev.c.  I thought
about that several times but haven't convinced myself it's worth it;
even with the code to handle tunneling the get_hash function is still
pretty elegant (I believe ipip support is just two more lines by the
way).