diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 49793567a..0dc84f820 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -83,6 +83,9 @@ VLOG_DEFINE_THIS_MODULE(dpif_netdev);
#define MAX_RECIRC_DEPTH 6
DEFINE_STATIC_PER_THREAD_DATA(uint32_t, recirc_depth, 0)
+/* Use instant packet send by default. */
+#define DEFAULT_TX_FLUSH_INTERVAL 0
+
/* Configuration parameters. */
enum { MAX_FLOWS = 65536 }; /* Maximum number of flows in flow table. */
enum { MAX_METERS = 65536 }; /* Maximum number of meters. */
@@ -269,6 +272,9 @@ struct dp_netdev {
struct hmap ports;
struct seq *port_seq; /* Incremented whenever a port changes. */
+ /* The time that a packet can wait in output batch for sending. */
+ atomic_uint32_t tx_flush_interval;
+
/* Meters. */
struct ovs_mutex meter_locks[N_METER_LOCKS];
struct dp_meter *meters[MAX_METERS]; /* Meter bands. */
@@ -496,6 +502,7 @@ struct tx_port {
int qid;
long long last_used;
struct hmap_node node;
+ long long flush_time;
struct dp_packet_batch output_pkts;
struct dp_netdev_rxq *output_pkts_rxqs[NETDEV_MAX_BURST];
};
@@ -577,6 +584,9 @@ struct dp_netdev_pmd_thread {
* than 'cmap_count(dp->poll_threads)'. */
uint32_t static_tx_qid;
+ /* Number of filled output batches. */
+ int n_output_batches;
+
struct ovs_mutex port_mutex; /* Mutex for 'poll_list' and 'tx_ports'. */
/* List of rx queues to poll. */
struct hmap poll_list OVS_GUARDED;
@@ -666,8 +676,9 @@ static void dp_netdev_add_rxq_to_pmd(struct dp_netdev_pmd_thread *pmd,
static void dp_netdev_del_rxq_from_pmd(struct dp_netdev_pmd_thread *pmd,
struct rxq_poll *poll)
OVS_REQUIRES(pmd->port_mutex);
-static void
-dp_netdev_pmd_flush_output_packets(struct dp_netdev_pmd_thread *pmd);
+static int
+dp_netdev_pmd_flush_output_packets(struct dp_netdev_pmd_thread *pmd,
+ bool force);
static void reconfigure_datapath(struct dp_netdev *dp)
OVS_REQUIRES(dp->port_mutex);
@@ -1241,6 +1252,7 @@ create_dp_netdev(const char *name, const struct dpif_class *class,
conntrack_init(&dp->conntrack);
atomic_init(&dp->emc_insert_min, DEFAULT_EM_FLOW_INSERT_MIN);
+ atomic_init(&dp->tx_flush_interval, DEFAULT_TX_FLUSH_INTERVAL);
cmap_init(&dp->poll_threads);
@@ -2907,7 +2919,7 @@ dpif_netdev_execute(struct dpif *dpif, struct dpif_execute *execute)
dp_packet_batch_init_packet(&pp, execute->packet);
dp_netdev_execute_actions(pmd, &pp, false, execute->flow,
execute->actions, execute->actions_len);
- dp_netdev_pmd_flush_output_packets(pmd);
+ dp_netdev_pmd_flush_output_packets(pmd, true);
if (pmd->core_id == NON_PMD_CORE_ID) {
ovs_mutex_unlock(&dp->non_pmd_mutex);
@@ -2956,6 +2968,16 @@ dpif_netdev_set_config(struct dpif *dpif, const struct smap *other_config)
smap_get_ullong(other_config, "emc-insert-inv-prob",
DEFAULT_EM_FLOW_INSERT_INV_PROB);
uint32_t insert_min, cur_min;
+ uint32_t tx_flush_interval, cur_tx_flush_interval;
+
+ tx_flush_interval = smap_get_int(other_config, "tx-flush-interval",
+ DEFAULT_TX_FLUSH_INTERVAL);
+ atomic_read_relaxed(&dp->tx_flush_interval, &cur_tx_flush_interval);
+ if (tx_flush_interval != cur_tx_flush_interval) {
+ atomic_store_relaxed(&dp->tx_flush_interval, tx_flush_interval);
+ VLOG_INFO("Flushing interval for tx queues set to %"PRIu32" us",
+ tx_flush_interval);
+ }
if (!nullable_string_is_equal(dp->pmd_cmask, cmask)) {
free(dp->pmd_cmask);
@@ -3150,7 +3172,7 @@ dp_netdev_rxq_get_intrvl_cycles(struct dp_netdev_rxq *rx, unsigned idx)
return processing_cycles;
}
-static void
+static int
dp_netdev_pmd_flush_output_on_port(struct dp_netdev_pmd_thread *pmd,
struct tx_port *p)
{
@@ -3160,6 +3182,7 @@ dp_netdev_pmd_flush_output_on_port(struct dp_netdev_pmd_thread *pmd,
bool dynamic_txqs;
struct cycle_timer timer;
uint64_t cycles;
+ uint32_t tx_flush_interval;
cycle_timer_start(&pmd->perf_stats, &timer);
@@ -3176,6 +3199,13 @@ dp_netdev_pmd_flush_output_on_port(struct dp_netdev_pmd_thread *pmd,
netdev_send(p->port->netdev, tx_qid, &p->output_pkts, dynamic_txqs);
dp_packet_batch_init(&p->output_pkts);
+ /* Update time of the next flush. */
+ atomic_read_relaxed(&pmd->dp->tx_flush_interval, &tx_flush_interval);
+ p->flush_time = pmd->ctx.now + tx_flush_interval;
+
+ ovs_assert(pmd->n_output_batches > 0);
+ pmd->n_output_batches--;
+
pmd_perf_update_counter(&pmd->perf_stats, PMD_STAT_SENT_PKTS, output_cnt);
pmd_perf_update_counter(&pmd->perf_stats, PMD_STAT_SENT_BATCHES, 1);
@@ -3188,18 +3218,28 @@ dp_netdev_pmd_flush_output_on_port(struct dp_netdev_pmd_thread *pmd,
RXQ_CYCLES_PROC_CURR, cycles);
}
}
+
+ return output_cnt;
}
-static void
-dp_netdev_pmd_flush_output_packets(struct dp_netdev_pmd_thread *pmd)
+static int
+dp_netdev_pmd_flush_output_packets(struct dp_netdev_pmd_thread *pmd,
+ bool force)
{
struct tx_port *p;
+ int output_cnt = 0;
+
+ if (!pmd->n_output_batches) {
+ return 0;
+ }
HMAP_FOR_EACH (p, node, &pmd->send_port_cache) {
- if (!dp_packet_batch_is_empty(&p->output_pkts)) {
- dp_netdev_pmd_flush_output_on_port(pmd, p);
+ if (!dp_packet_batch_is_empty(&p->output_pkts)
+ && (force || pmd->ctx.now >= p->flush_time)) {
+ output_cnt += dp_netdev_pmd_flush_output_on_port(pmd, p);
}
}
+ return output_cnt;
}
static int
@@ -3210,7 +3250,7 @@ dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
struct dp_packet_batch batch;
struct cycle_timer timer;
int error;
- int batch_cnt = 0;
+ int batch_cnt = 0, output_cnt = 0;
uint64_t cycles;
/* Measure duration for polling and processing rx burst. */
@@ -3232,7 +3272,7 @@ dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
cycles = cycle_timer_stop(&pmd->perf_stats, &timer);
dp_netdev_rxq_add_cycles(rxq, RXQ_CYCLES_PROC_CURR, cycles);
- dp_netdev_pmd_flush_output_packets(pmd);
+ output_cnt = dp_netdev_pmd_flush_output_packets(pmd, false);
} else {
/* Discard cycles. */
cycle_timer_stop(&pmd->perf_stats, &timer);
@@ -3246,7 +3286,7 @@ dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
pmd->ctx.last_rxq = NULL;
- return batch_cnt;
+ return batch_cnt + output_cnt;
}
static struct tx_port *
@@ -3869,6 +3909,7 @@ dpif_netdev_run(struct dpif *dpif)
struct dp_netdev *dp = get_dp_netdev(dpif);
struct dp_netdev_pmd_thread *non_pmd;
uint64_t new_tnl_seq;
+ bool need_to_flush = true;
ovs_mutex_lock(&dp->port_mutex);
non_pmd = dp_netdev_get_pmd(dp, NON_PMD_CORE_ID);
@@ -3879,13 +3920,22 @@ dpif_netdev_run(struct dpif *dpif)
int i;
for (i = 0; i < port->n_rxq; i++) {
- dp_netdev_process_rxq_port(non_pmd,
- &port->rxqs[i],
- port->port_no);
+ if (dp_netdev_process_rxq_port(non_pmd,
+ &port->rxqs[i],
+ port->port_no)) {
+ need_to_flush = false;
+ }
}
}
}
- pmd_thread_ctx_time_update(non_pmd);
+ if (need_to_flush) {
+ /* We didn't receive anything in the process loop.
+ * Check if we need to send something.
+ * There was no time updates on current iteration. */
+ pmd_thread_ctx_time_update(non_pmd);
+ dp_netdev_pmd_flush_output_packets(non_pmd, false);
+ }
+
dpif_netdev_xps_revalidate_pmd(non_pmd, false);
ovs_mutex_unlock(&dp->non_pmd_mutex);
@@ -3936,6 +3986,8 @@ pmd_free_cached_ports(struct dp_netdev_pmd_thread *pmd)
{
struct tx_port *tx_port_cached;
+ /* Flush all the queued packets. */
+ dp_netdev_pmd_flush_output_packets(pmd, true);
/* Free all used tx queue ids. */
dpif_netdev_xps_revalidate_pmd(pmd, true);
@@ -4066,6 +4118,7 @@ reload:
cycles_counter_update(s);
for (;;) {
uint64_t iter_packets = 0;
+
pmd_perf_start_iteration(s);
for (i = 0; i < poll_cnt; i++) {
process_packets =
@@ -4074,15 +4127,20 @@ reload:
iter_packets += process_packets;
}
+ if (!iter_packets) {
+ /* We didn't receive anything in the process loop.
+ * Check if we need to send something.
+ * There was no time updates on current iteration. */
+ pmd_thread_ctx_time_update(pmd);
+ iter_packets += dp_netdev_pmd_flush_output_packets(pmd, false);
+ }
+
if (lc++ > 1024) {
bool reload;
lc = 0;
coverage_try_clear();
- /* It's possible that the time was not updated on current
- * iteration, if there were no received packets. */
- pmd_thread_ctx_time_update(pmd);
dp_netdev_pmd_try_optimize(pmd, poll_list, poll_cnt);
if (!ovsrcu_try_quiesce()) {
emc_cache_slow_sweep(&pmd->flow_cache);
@@ -4521,6 +4579,7 @@ dp_netdev_configure_pmd(struct dp_netdev_pmd_thread *pmd, struct dp_netdev *dp,
pmd->core_id = core_id;
pmd->numa_id = numa_id;
pmd->need_reload = false;
+ pmd->n_output_batches = 0;
ovs_refcount_init(&pmd->ref_cnt);
latch_init(&pmd->exit_latch);
@@ -4710,6 +4769,7 @@ dp_netdev_add_port_tx_to_pmd(struct dp_netdev_pmd_thread *pmd,
tx->port = port;
tx->qid = -1;
+ tx->flush_time = 0LL;
dp_packet_batch_init(&tx->output_pkts);
hmap_insert(&pmd->tx_ports, &tx->node, hash_port_no(tx->port->port_no));
@@ -5404,12 +5464,16 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
dp_netdev_pmd_flush_output_on_port(pmd, p);
}
#endif
- if (OVS_UNLIKELY(dp_packet_batch_size(&p->output_pkts)
- + dp_packet_batch_size(packets_) > NETDEV_MAX_BURST)) {
- /* Some packets was generated while input batch processing.
- * Flush here to avoid overflow. */
+ if (dp_packet_batch_size(&p->output_pkts)
+ + dp_packet_batch_size(packets_) > NETDEV_MAX_BURST) {
+ /* Flush here to avoid overflow. */
dp_netdev_pmd_flush_output_on_port(pmd, p);
}
+
+ if (dp_packet_batch_is_empty(&p->output_pkts)) {
+ pmd->n_output_batches++;
+ }
+
DP_PACKET_BATCH_FOR_EACH (packet, packets_) {
p->output_pkts_rxqs[dp_packet_batch_size(&p->output_pkts)] =
pmd->ctx.last_rxq;
diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index 58c0ebd4b..61fb7b17f 100644
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -359,6 +359,22 @@
+
+
+ Specifies the time in microseconds that a packet can wait in output
+ batch for sending i.e. amount of time that packet can spend in an
+ intermediate output queue before sending to netdev.
+ This option can be used to configure balance between throughput
+ and latency. Lower values decreases latency while higher values
+ may be useful to achieve higher performance.
+
+
+ Defaults to 0 i.e. instant packet sending (latency optimized).
+
+
+