bridge: Fix high cpu utilization.

When there are more than one ovs-vswitchd processes started, only one process is enabled. The disabled processes should just sleep. However, a bug in ovs makes the disabled processes keep waking up on global connectivity sequence number which is never sync'ed. Consequently, those processes use 100% cpu. This commit fixes the bug by always sync up the connectivity sequence number for disabled processes. Reported-by: Ben Pfaff <[email protected]> Signed-off-by: Alex Wang <[email protected]> Acked-by: Joe Stringer <[email protected]>
subashd · Oct 1, 2014 · 6bef3c7 · 6bef3c7
1 parent d7fdacb
commit 6bef3c7
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diff --git a/tests/ovs-vswitchd.at b/tests/ovs-vswitchd.at
@@ -66,3 +66,40 @@ OVS_VSCTL_CHECK_RX_PKT([p1], [7])
 
 OVS_VSWITCHD_STOP
 AT_CLEANUP
+
+dnl ----------------------------------------------------------------------
+AT_SETUP([ovs-vswitchd -- start additional ovs-vswitchd process])
+OVS_VSWITCHD_START
+
+# start another ovs-vswitchd process.
+ovs-vswitchd --log-file=fakelog &
+pid=`echo $!`
+
+# sleep for a while
+sleep 5
+
+# stop the process.
+kill $pid
+
+# check the fakelog, should only see one ERR for reporting
+# the existing ovs-vswitchd process and one WARN for killing
+# the process.
+AT_CHECK([grep ERR fakelog | wc -l], [0], [dnl
+1
+])
+
+AT_CHECK([grep WARN fakelog | wc -l], [0], [dnl
+1
+])
+
+AT_CHECK([grep ERR fakelog | sed -e 's/^.*ERR|//; s/pid [[0-9]]*//'], [0], [dnl
+another ovs-vswitchd process is running, disabling this process () until it goes away
+])
+
+# check the fakelog, the ERR log should be the last line.
+AT_CHECK([tail -n 2 fakelog | head -n 1 | sed -e 's/^.*ERR|//; s/pid [[0-9]]*//'], [0], [dnl
+another ovs-vswitchd process is running, disabling this process () until it goes away
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
@@ -2772,6 +2772,9 @@ bridge_run(void)
          * with the current situation of multiple ovs-vswitchd daemons,
          * disable system stats collection. */
         system_stats_enable(false);
+        /* This prevents the process from constantly waking up on
+         * connectivity seq. */
+        connectivity_seqno = seq_read(connectivity_seq_get());
         return;
     } else if (!ovsdb_idl_has_lock(idl)) {
         return;