tests: Fix threading race in "ofproto-dpif megaflow - learning" test.

Threaded ofproto-dpif uses a queue to pass packets from the forwarding
threads to the main thread for (mega)flow setup and for learning.  When
learning occurs, causing revalidations, this races against flow setup, so
that sometimes a datapath (mega)flow does get set up for a packet that
causes learning and sometimes it doesn't.  This caused this test to
sometimes fail because one megaflow or the other that was expected to be
set up was not.

This commit fixes the problem by sending a second packet in each flow.
These additional packets don't cause any additional changes to the flow
table but they do cause flows to be set up, fixing the problem.

Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/tests/ofproto-dpif.at b/tests/ofproto-dpif.at
index 46e1dea..4a22dc6 100644 (file)
--- a/tests/ofproto-dpif.at
+++ b/tests/ofproto-dpif.at
@@ -2581,8 +2581,15 @@ AT_DATA([flows.txt], [dnl
 table=0 in_port=1 actions=load:2->NXM_NX_REG0[[0..15]],learn(table=1,priority=65535,NXM_OF_ETH_SRC[[]],NXM_OF_VLAN_TCI[[0..11]],output:NXM_NX_REG0[[0..15]]),output:2
 ])
 AT_CHECK([ovs-ofctl add-flows br0 flows.txt])
-AT_CHECK([ovs-appctl netdev-dummy/receive p1 'in_port(1),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(src=10.0.0.2,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
-AT_CHECK([ovs-appctl netdev-dummy/receive p1 'in_port(1),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(src=10.0.0.4,dst=10.0.0.3,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+# We send each packet twice because the first packet in each flow causes the
+# flow table to change and thus revalidations, which (depending on timing)
+# can keep a megaflow from being installed.  The revalidations are done by
+# the second iteration, allowing the flows to be installed.
+for i in 1 2; do
+    AT_CHECK([ovs-appctl netdev-dummy/receive p1 'in_port(1),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(src=10.0.0.2,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+    AT_CHECK([ovs-appctl netdev-dummy/receive p1 'in_port(1),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(src=10.0.0.4,dst=10.0.0.3,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+    ovs-appctl time/warp 100
+done
 dnl The original flow is missing due to a revalidation.
 AT_CHECK([ovs-appctl dpif/dump-megaflows br0 | STRIP_XOUT], [0], [dnl
 skb_priority=0,ip,in_port=1,vlan_tci=0x0000/0x0fff,dl_src=50:54:00:00:00:09,nw_frag=no, n_subfacets:1, used:0.0s, Datapath actions: <del>