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authorFlorin Coras <fcoras@cisco.com>2018-05-21 17:47:40 -0700
committerDamjan Marion <dmarion@me.com>2018-10-25 10:13:18 +0000
commitd67f112063e6c57160a3d0260537b9dcfe23d217 (patch)
treec2d5251e7896290cc0a968fb2b4d6d9ba87aef17 /src/vnet/session/session_node.c
parent2fab01ee0f9b406584272968863eee16a3bb1fb9 (diff)
tcp/session: add tx pacer
Adds tx pacing infrastructure for transport protocols that want to use it. Particularly useful for connections with non-negligible rtt and constrained network throughput as it avoids large tx bursts that lead to local interface tx or network drops. By default the pacer is disabled. To enabled it for tcp, add tx-pacing to tcp's startup conf. We are still slightly inefficient in the handling of incoming packets in established state so the pacer slightly affect maximum throughput in low lacency scenarios. Change-Id: Id445b2ffcd64cce015f75b773f7d722faa0f7ca9 Signed-off-by: Florin Coras <fcoras@cisco.com>
Diffstat (limited to 'src/vnet/session/session_node.c')
-rw-r--r--src/vnet/session/session_node.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index c1aea6723b6..eb974397165 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -568,7 +568,8 @@ session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
ctx->transport_vft = transport_protocol_get_vft (tp);
ctx->tc = session_tx_get_transport (ctx, peek_data);
ctx->snd_mss = ctx->transport_vft->send_mss (ctx->tc);
- ctx->snd_space = ctx->transport_vft->send_space (ctx->tc);
+ ctx->snd_space =
+ transport_connection_max_tx_burst (ctx->tc, vm->clib_time.last_cpu_time);
if (ctx->snd_space == 0 || ctx->snd_mss == 0)
{
vec_add1 (smm->pending_event_vector[thread_index], *e);
@@ -685,6 +686,7 @@ session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
_vec_len (smm->tx_buffers[thread_index]) = n_bufs;
*n_tx_packets += ctx->n_segs_per_evt;
+ transport_connection_update_tx_stats (ctx->tc, ctx->max_len_to_snd);
vlib_put_next_frame (vm, node, next_index, n_left_to_next);
/* If we couldn't dequeue all bytes mark as partially read */
@@ -743,6 +745,17 @@ session_event_get_session (session_event_t * e, u8 thread_index)
return session_get_if_valid (e->fifo->master_session_index, thread_index);
}
+static void
+session_update_dispatch_period (session_manager_main_t * smm, f64 now,
+ u32 thread_index)
+{
+ f64 sample, prev_period = smm->dispatch_period[thread_index], a = 0.8;
+
+ sample = now - smm->last_vlib_time[thread_index];
+ smm->dispatch_period[thread_index] = a * sample + (1 - a) * prev_period;
+ smm->last_vlib_time[thread_index] = now;
+}
+
static uword
session_queue_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
vlib_frame_t * frame)
@@ -764,6 +777,7 @@ session_queue_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
/*
* Update transport time
*/
+ session_update_dispatch_period (smm, now, thread_index);
transport_update_time (now, thread_index);
/*