Thanks Han,

Acked-by: Mark Michelson <>

On 3/28/24 02:58, Han Zhou wrote:
The ovn-ofctrl-wait-before-clear setting is designed to minimize
downtime during the initial start-up of the ovn-controller. For this
purpose, the ovn-controller should wait only once upon entering the
S_WAIT_BEFORE_CLEAR state for the first time. Subsequent reconnections
to the OVS, such as those occurring during an OVS restart/upgrade,
should not trigger this wait. However, the current implemention always
waits for the configured time in the S_WAIT_BEFORE_CLEAR state, which
can inadvertently delay flow installations during OVS restart/upgrade,
potentially causing more harm than good. (The extent of the impact
varies based on the method used to restart OVS, including whether flow
save/restore tools and the flow-restore-wait feature are employed.)

This patch avoids the unnecessary wait after the initial one.

Fixes: 896adfd2d8b3 ("ofctrl: Support ovn-ofctrl-wait-before-clear to reduce down 
time during upgrade.")
Signed-off-by: Han Zhou <>
v2: Addressed Mark's comments - made test case more reliable.

  controller/ofctrl.c     | 1 -
  tests/ | 9 +++++++--
  2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/controller/ofctrl.c b/controller/ofctrl.c
index 6ca2ea4ce63d..6a2564604aa1 100644
--- a/controller/ofctrl.c
+++ b/controller/ofctrl.c
@@ -634,7 +634,6 @@ run_S_WAIT_BEFORE_CLEAR(void)
      if (!wait_before_clear_time ||
          (wait_before_clear_expire &&
           time_msec() >= wait_before_clear_expire)) {
-        wait_before_clear_expire = 0;
          state = S_CLEAR_FLOWS;
diff --git a/tests/ b/tests/
index fdcc5aab2bcf..3202f0beff46 100644
--- a/tests/
+++ b/tests/
@@ -2324,10 +2324,15 @@ lflow_run_2=$(ovn-appctl -t ovn-controller 
coverage/read-counter lflow_run)
  AT_CHECK_UNQUOTED([echo $lflow_run_1], [0], [$lflow_run_2
-# Restart OVS this time, and wait until flows are reinstalled
+# Restart OVS this time. Flows should be reinstalled without waiting.
  start_daemon ovs-vswitchd --enable-dummy=system -vvconn -vofproto_dpif 
-OVS_WAIT_UNTIL([ovs-ofctl dump-flows br-int | grep -F | grep -vF])
+# Sync to make sure ovn-controller is given enough time to install the flows.
+check ovn-nbctl --wait=hv sync
+# Flow should be installed without any extra waiting.
+AT_CHECK([ovs-ofctl dump-flows br-int | grep -F | grep -vF], 
[0], [ignore])
check ovn-nbctl --wait=hv lb-add lb3 \
  -- ls-lb-add ls1 lb3

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