diff mbox series

[ovs-dev,RFC] odp-execute: dp_hash HW offload inconsistency.

Message ID AM4PR05MB318736A5773157AF54417E2EBC3E0@AM4PR05MB3187.eurprd05.prod.outlook.com
State RFC
Headers show
Series [ovs-dev,RFC] odp-execute: dp_hash HW offload inconsistency. | expand

Commit Message

Roni Bar Yanai Jan. 8, 2020, 11:08 a.m. UTC 
Hi Ilya,

I have a setup with vxlan,  and then I do dp_hash (after pop).
First packet does pop in SW, so RSS is invalidated (and anyway it was probably
 calculated on outer),  dp_hash is calculated again SW.
Following packet will do decap in HW so packet has a valid internal RSS (mark+rss),
And it is used as the hash. I have inconsistency between the packets that passed
 through SW and packet that were offloaded with the same 5-tuple (internal).

I know vxlan pop is not offload yet, but we hope it will soon.
I thought of solving this issue by calling netdev_offload_dpdk layer to calc the hash in case
when HW offload Is enabled. So it will be the same hash for both cases.
dp_hash HW offload without a tunnel, will have the same issue, as HW will use some hash not
 necessarily the same as RSS configuration, and even if RSS is used, in SW there is another
salt on top of that, so packet with same 5-tuple offload vs not offloaded will get different hash.


What do you think?

BR,
Roni
diff mbox series

Patch

diff --git a/lib/odp-execute.c b/lib/odp-execute.c
index 563ad1d..26dc907 100644
--- a/lib/odp-execute.c
+++ b/lib/odp-execute.c
@@ -822,14 +822,18 @@  odp_execute_actions(void *dp, struct dp_packet_batch *batch, bool steal,
                 DP_PACKET_BATCH_FOR_EACH (i, packet, batch) {
                     /* 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);
-                        hash = hash_int(hash, hash_act->hash_basis);
+                    if (netdev_is_flow_api_enabled()) {
+                            hash = netdev_offload_dpdk_set_dp_hash(packet);
                     } else {
-                        flow_extract(packet, &flow);
-                        hash = flow_hash_5tuple(&flow, hash_act->hash_basis);
-                    }
-                    packet->md.dp_hash = hash;
+
+                        if (dp_packet_rss_valid(packet)) {
+                            hash = dp_packet_get_rss_hash(packet);
+                            hash = hash_int(hash, hash_act->hash_basis);
+                        } else {
+                            flow_extract(packet, &flow);
+                            hash = flow_hash_5tuple(&flow, hash_act->hash_basis);
+                        }
+                        packet->md.dp_hash = hash;
                 }
                 break;
             }