[ovs-dev] [PATCH v2] datapath: Remove tunnel header caching.

[Ben Pfaff]

On Thu, Oct 25, 2012 at 11:14:38AM -0700, Pravin B Shelar wrote:
> v1-v2:
> 	- Fixed capwap fragment case.
> 	- simplified tnl_send.
> --8<--------------------------cut here-------------------------->8--
> 
> Tunnel caching was added to reduce CPU utilization on TX path
> by caching packet header, So performance gain is directly proportional
> to number of skbs transferred. But with help of offloads skb are getting
> larger. So there are less number of skbs. Therefore header caching does
> not shows similar gains we seen in past. And now kernel 3.6 has removed
> dst caching from networking which makes header caching even more tricky.
> So this commit removes header caching from OVS tunnelling.
> 
> Signed-off-by: Pravin B Shelar <pshelar at nicira.com>

Is there any benefit in adding a comment to tunnel.h remarking that
the bit 1<<6 is reserved because it was previously used?  (Maybe not,
if we're deleting this interface entirely in another version.)