[ovs-dev] [PATCH] odp-execute: Reuse rss hash in OVS_ACTION_ATTR_HASH.

[Ilya Maximets]

If RSS hash exists in a packet it can be reused instead of
5 tuple hash re-calculation in OVS_ACTION_ATTR_HASH. This
leads to increasing the performance of sending packets to
the OVS bonding in userspace datapath up to 10-15%.

Signed-off-by: Ilya Maximets <i.maximets at samsung.com>
---
 lib/odp-execute.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/odp-execute.c b/lib/odp-execute.c
index d656334..471a364 100644
--- a/lib/odp-execute.c
+++ b/lib/odp-execute.c
@@ -646,8 +646,17 @@ odp_execute_actions(void *dp, struct dp_packet_batch *batch, bool steal,
                 uint32_t hash;
 
                 DP_PACKET_BATCH_FOR_EACH (packet, batch) {
-                    flow_extract(packet, &flow);
-                    hash = flow_hash_5tuple(&flow, hash_act->hash_basis);
+                    /* RSS hash can be used here instead of 5tuple for
+                     * performance reasons. */
+                    if (dp_packet_rss_valid(packet)) {
+                        hash = dp_packet_get_rss_hash(packet);
+                        if (hash_act->hash_basis) {
+                            hash = hash_finish(hash, hash_act->hash_basis);
+                        }
+                    } else {
+                        flow_extract(packet, &flow);
+                        hash = flow_hash_5tuple(&flow, hash_act->hash_basis);
+                    }
                     packet->md.dp_hash = hash;
                 }
             } else {
-- 
2.7.4