[ovs-discuss] Isn't there any way to use RSS hash instead of jhash in flow_hash()

[Ben Pfaff]

On Wed, May 24, 2017 at 04:01:28PM +0900, Heung Sik Choi wrote:
> Thank you for replying
> 
> Are you saying that you want to add RSS to the datapath to
> move packets to different queues? Which queues? Or do you just want to
> create a Toeplitz hashing algorithm function that will return a hash
> value and it doesn't really have anything to do with RSS?
> 
> Sorry to confuse you. specifically, I think a design where skb structure
> has 'rss hash value' and ovs' datapath use this value when it lookup flow
> table. the rss hash value can get in NIC driver(ex. ixgbe), and can be
> inserted in skb structure. Also If I replace the jhash2 in flow_hash()
> with Toeplitz hash, the 'rss hash' can be used to hash in ovs. How do you
> think about it? please let me know if you have any insights.

If flow_hash() just returns a fixed hash value, then it won't hash the
right parts of the packet.  It takes a key range argument for a reason.