Re: [virtio-dev] RE: [PATCH v15] virtio-net: support inner header hash

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Jun 08, 2023 at 02:45:15PM +0000, Parav Pandit wrote:
> 
> > From: Michael S. Tsirkin <mst@redhat.com>
> > Sent: Thursday, June 8, 2023 10:42 AM
> 
> > > > 2. hand over to RSS the ability to specify a hash based on the outer source
> > port.
> > > > That is, we can add VIRTIO_NET_RSS_HASH_TUNNEL_SRC_PORT_UDP_{v4,
> > v6,
> > > > EX} in \field{supported_hash_types} to indicate that the hash should
> > > > be calculated using the outer source port for all UDP tunneling protocols.
> > > > This approach removes the need for \field{hash_option} and makes the
> > > > line between VIRTIO_NET_F_HASH_TUNNEL and VIRTIO_NET_F_RSS clearer.
> > > >
> > > #2 is preferred.
> > >
> > > But I must be missing something.
> > > Without VIRTIO_NET_RSS_HASH_TUNNEL_SRC_PORT_UDP_X, today if one
> > wants
> > > to do RSS based on the outer UDP ports, It is already supported by the RSS
> > (even in presence of the inner header).
> > >
> > > So why do have to introduce
> > VIRTIO_NET_RSS_HASH_TUNNEL_SRC_PORT_UDP_X?
> > 
> > they want an option to ignore all other header fields.
> 
> Than that looks like rss config extension on which fields of the packet to use for RSS.

yes, but also, only for specific packet type and dest port #s.


-- 
MST