[ovs-dev] [PATCH] tunnels: Don't initialize unnecessary packet metadata.

[Ben Pfaff]

On Tue, Jun 30, 2015 at 11:19:08PM -0700, Jesse Gross wrote:
> The addition of Geneve options to packet metadata significantly
> expanded its size. It was reported that this can decrease performance
> for DPDK ports by up to 25% since we need to initialize the whole
> structure on each packet receive.
> 
> It is not really necessary to zero out the entire structure because
> miniflow_extract() only copies the tunnel metadata when particular
> fields indicate that it is valid. Therefore, as long as we zero out
> these fields when the metadata is initialized and ensure that the
> rest of the structure is correctly set in the presence of a tunnel,
> we can avoid touching the tunnel fields on packet reception.
> 
> Reported-by: Ciara Loftus <ciara.loftus at intel.com>
> Signed-off-by: Jesse Gross <jesse at nicira.com>

Acked-by: Ben Pfaff <blp at nicira.com>