On Fri, 6 Oct 2023 16:47:21 -0600 Ahmed Zaki wrote: > Symmetric RSS hash functions are beneficial in applications that monitor > both Tx and Rx packets of the same flow (IDS, software firewalls, ..etc). > Getting all traffic of the same flow on the same RX queue results in > higher CPU cache efficiency. > > Only fields that has counterparts in the other direction can be > accepted; IP src/dst and L4 src/dst ports. > > The user may request RSS hash symmetry for a specific flow type, via: > > # ethtool -N|-U eth0 rx-flow-hash <flow_type> s|d|f|n symmetric > > or turn symmetry off (asymmetric) by: > > # ethtool -N|-U eth0 rx-flow-hash <flow_type> s|d|f|n Thanks for the changes, code looks good! The question left unanswered is whether we should care about the exact implementation of the symmetry (xor, xor duplicate, sort fields). Toeplitz-based RSS is very precisely specified, so we may want to carry that precision into the symmetric behavior. I have a weak preference to do so... but no willingness to argue with you, so let me put Willem on the spot and have him make a decision :) Please make sure to CC Willem and anyone else who commented on previous revisions on future versions!
