[ovs-dev] [RFC] packets: Do not initialize ct_orig_tuple.

[Daniele Di Proietto]

Commit daf4d3c18da4("odp: Support conntrack orig tuple key.") introduced
new fields in struct 'pkt_metadata'.  pkt_metadata_init() is called for
every packet in the userspace datapath.  When testing a simple single
flow case with DPDK, we observe a lower throughput after the above
commit (it was 14.88 Mpps before, it is 13 Mpps after).

This patch skips initializing ct_orig_tuple in pkt_metadata_init().
It should be enough to initialize ct_state, because nobody should look
at ct_orig_tuple unless ct_state is != 0.

CC: Jarno Rajahalme <jarno at ovn.org>
Signed-off-by: Daniele Di Proietto <diproiettod at vmware.com>
---
I'm sending this as an RFC because I didn't check very carefully if we can
really avoid initializing ct_orig_tuple.

Maybe there are better solutions to this problem.
---
 lib/packets.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/packets.h b/lib/packets.h
index a5a483bc8..6f1791c7a 100644
--- a/lib/packets.h
+++ b/lib/packets.h
@@ -129,7 +129,7 @@ pkt_metadata_init(struct pkt_metadata *md, odp_port_t port)
     /* It can be expensive to zero out all of the tunnel metadata. However,
      * we can just zero out ip_dst and the rest of the data will never be
      * looked at. */
-    memset(md, 0, offsetof(struct pkt_metadata, in_port));
+    memset(md, 0, offsetof(struct pkt_metadata, ct_orig_tuple));
     md->tunnel.ip_dst = 0;
     md->tunnel.ipv6_dst = in6addr_any;
 
-- 
2.11.0