bfd/cfm: Check status change before update status to database.

This commit adds boolean flag in bfd/cfm module for checking
status change.  If there is no status change, the current
update to OVS database will skip the bfd/cfm session.

In the experiment with 5K bfd sessions, when one session is
flapping at rate of every 0.3 second, this patch reduces the
cpu utilization of the ovs-vswitchd thread from 13 to 6.

Signed-off-by: Alex Wang <alexw@nicira.com>
Acked-by: Joe Stringer <joestringer@nicira.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/bfd.h b/lib/bfd.h
index 4e7d4cb46..039b4dd96 100644
--- a/lib/bfd.h
+++ b/lib/bfd.h
@@ -49,6 +49,7 @@ void bfd_unref(struct bfd *);
 
 void bfd_account_rx(struct bfd *, const struct dpif_flow_stats *);
 bool bfd_forwarding(struct bfd *);
+bool bfd_check_status_change(struct bfd *);
 void bfd_get_status(const struct bfd *, struct smap *);
 void bfd_set_netdev(struct bfd *, const struct netdev *);
 long long int bfd_wake_time(const struct bfd *);