When there is no incoming data traffic in the tunnel, BFD decay allows the bfd session to increase the min_rx. This is helpful in that usually some tunnels are rarely used. And cpu consumption can be reduced by processing fewer bfd control packets.
Signed-off-by: Alex Wang <[email protected]> --- lib/bfd.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++-- lib/bfd.h | 6 +++- ofproto/ofproto-dpif.c | 3 +- vswitchd/vswitch.xml | 7 ++++ 4 files changed, 100 insertions(+), 5 deletions(-) diff --git a/lib/bfd.c b/lib/bfd.c index aa1a3f7..4a6a0a6 100644 --- a/lib/bfd.c +++ b/lib/bfd.c @@ -152,6 +152,9 @@ struct bfd { bool cpath_down; /* Concatenated Path Down. */ uint8_t mult; /* bfd.DetectMult. */ + struct netdev *netdev; + uint64_t rx_packets; /* Packets received by 'netdev'. */ + enum state state; /* bfd.SessionState. */ enum state rmt_state; /* bfd.RemoteSessionState. */ @@ -182,6 +185,13 @@ struct bfd { int ref_cnt; int forwarding_override; /* Manual override of 'forwarding' status. */ + + /* BFD decay related variables. */ + bool decay_enabled; /* Flag that enables bfd decay. */ + int decay_count; /* Counter of bfd control packets, */ + /* between decay detect interval. */ + int decay_interval; + long long int decay_detect_time; }; static bool bfd_in_poll(const struct bfd *); @@ -191,6 +201,9 @@ static const char *bfd_state_str(enum state); static long long int bfd_min_tx(const struct bfd *); static long long int bfd_tx_interval(const struct bfd *); static long long int bfd_rx_interval(const struct bfd *); +static void bfd_decay_compute_interval(struct bfd *); +static uint64_t bfd_rx_packets(struct bfd *); +static void bfd_decay(struct bfd *); static void bfd_set_next_tx(struct bfd *); static void bfd_set_state(struct bfd *, enum state, enum diag); static uint32_t generate_discriminator(void); @@ -243,7 +256,8 @@ bfd_get_status(const struct bfd *bfd, struct smap *smap) * Also returns NULL if cfg is NULL. */ struct bfd * bfd_configure(struct bfd *bfd, const char *name, - const struct smap *cfg) + const struct smap *cfg, + struct netdev *netdev) { static uint16_t udp_src = 0; static bool init = false; @@ -276,6 +290,11 @@ bfd_configure(struct bfd *bfd, const char *name, bfd->min_tx = 1000; bfd->mult = 3; bfd->ref_cnt = 1; + bfd->netdev = netdev; + bfd->rx_packets = 0; + bfd->decay_count = 0; + bfd->decay_interval = 0; + bfd->decay_detect_time = 0; /* RFC 5881 section 4 * The source port MUST be in the range 49152 through 65535. The same @@ -309,6 +328,11 @@ bfd_configure(struct bfd *bfd, const char *name, bfd_poll(bfd); } + bfd->decay_enabled = smap_get_bool(cfg, "decay_enable", false); + if (bfd->decay_enabled) { + bfd_decay_compute_interval(bfd); + } + cpath_down = smap_get_bool(cfg, "cpath_down", false); if (bfd->cpath_down != cpath_down) { bfd->cpath_down = cpath_down; @@ -360,11 +384,19 @@ bfd_wait(const struct bfd *bfd) void bfd_run(struct bfd *bfd) { - if (bfd->state > STATE_DOWN && time_msec() >= bfd->detect_time) { + long long int cur_time = time_msec(); + + if (bfd->state > STATE_DOWN && cur_time >= bfd->detect_time) { bfd_set_state(bfd, STATE_DOWN, DIAG_EXPIRED); } - if (bfd->min_tx != bfd->cfg_min_tx || bfd->min_rx != bfd->cfg_min_rx) { + if (bfd->state > STATE_DOWN && bfd->decay_enabled + && cur_time >= bfd->decay_detect_time) { + bfd_decay(bfd); + } + + if (!bfd->decay_enabled && + (bfd->min_tx != bfd->cfg_min_tx || bfd->min_rx != bfd->cfg_min_rx)) { bfd_poll(bfd); } } @@ -497,6 +529,10 @@ bfd_process_packet(struct bfd *bfd, const struct flow *flow, log_msg(VLL_DBG, msg, "Received BFD control message", bfd); + if (bfd->decay_enabled) { + bfd->decay_count++; + } + if (version != BFD_VERSION) { log_msg(VLL_WARN, msg, "Incorrect version", bfd); return; @@ -804,6 +840,53 @@ bfd_set_state(struct bfd *bfd, enum state state, enum diag diag) } } +/* Compute the decay interval based on the configured min_rx. + * This function should be invoked only by bfd_configure(). */ +static void +bfd_decay_compute_interval(struct bfd *bfd) +{ + bfd->decay_interval = bfd->cfg_min_rx * bfd->mult * bfd->mult * bfd->mult; + bfd->decay_detect_time = time_msec() + bfd->decay_interval; +} + +static uint64_t +bfd_rx_packets(struct bfd *bfd) +{ + struct netdev_stats stats; + + if (bfd->netdev && !netdev_get_stats(bfd->netdev, &stats)) { + return stats.rx_packets; + } else { + return 0; + } +} + +static void +bfd_decay(struct bfd *bfd) +{ + uint64_t rx_packets = bfd_rx_packets(bfd); + int64_t diff; + + diff = abs(rx_packets - bfd->rx_packets - bfd->decay_count); + + if (diff <= (4000 / bfd->min_rx + 1)) { + /* Decay. */ + if (bfd->min_rx != bfd->decay_interval) { + bfd->min_rx += bfd->cfg_min_rx * bfd->mult; + if (bfd->min_rx > bfd->decay_interval) { + bfd->min_rx = bfd->decay_interval; + } + } + } else { + /* Restore the min_rx. */ + bfd->min_rx = bfd->cfg_min_rx; + } + + bfd->decay_count = 0; + bfd->rx_packets = rx_packets; + bfd->decay_detect_time = bfd->decay_interval + time_msec(); +} + static uint32_t generate_discriminator(void) { diff --git a/lib/bfd.h b/lib/bfd.h index ab854d8..6e90cc3 100644 --- a/lib/bfd.h +++ b/lib/bfd.h @@ -18,9 +18,12 @@ #define BFD_PACKET_LEN 24 #define BFD_DEST_PORT 3784 +#include <stdlib.h> #include <stdbool.h> #include <inttypes.h> +#include "netdev.h" + struct bfd; struct flow; struct flow_wildcards; @@ -39,7 +42,8 @@ void bfd_process_packet(struct bfd *, const struct flow *, const struct ofpbuf *); struct bfd *bfd_configure(struct bfd *, const char *name, - const struct smap *smap); + const struct smap *smap, + struct netdev *netdev); struct bfd *bfd_ref(const struct bfd *); void bfd_unref(struct bfd *); diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c index 9ba7671..c9bd19a 100644 --- a/ofproto/ofproto-dpif.c +++ b/ofproto/ofproto-dpif.c @@ -1882,7 +1882,8 @@ set_bfd(struct ofport *ofport_, const struct smap *cfg) struct bfd *old; old = ofport->bfd; - ofport->bfd = bfd_configure(old, netdev_get_name(ofport->up.netdev), cfg); + ofport->bfd = bfd_configure(old, netdev_get_name(ofport->up.netdev), + cfg, ofport->up.netdev); if (ofport->bfd != old) { ofproto->backer->need_revalidate = REV_RECONFIGURE; } diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml index 6c08f70..846fc38 100644 --- a/vswitchd/vswitch.xml +++ b/vswitchd/vswitch.xml @@ -1880,6 +1880,13 @@ specified. Defaults to <code>100</code>. </column> + <column name="bfd" key="decay_enable" type='{"type": "boolean"}'> + Allow the BFD session decay the min_rx when there is no incoming data + traffic in the tunnel. This is helpful in that usually some tunnels + are rarely used. And decaying the min_rx can reduce the number of BFD + control packets processed and the cpu consumption. + </column> + <column name="bfd" key="cpath_down" type='{"type": "boolean"}'> Concatenated path down may be used when the local system should not have traffic forwarded to it for some reason other than a connectivty -- 1.7.9.5 _______________________________________________ dev mailing list [email protected] http://openvswitch.org/mailman/listinfo/dev
