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authorFlorin Coras <fcoras@cisco.com>2017-06-09 21:07:32 -0700
committerDamjan Marion <dmarion.lists@gmail.com>2017-06-19 14:06:34 +0000
commitf03a59ab008908f98fd7d1b187a8c0fb78b01add (patch)
tree8ce1ab091e288d5edbc5df712f668e2e4888c90e /src/vnet/tcp/tcp_input.c
parent328dbc886d7acd3491cff86a7a85176e511acf35 (diff)
Overall tcp performance improvements (VPP-846)
- limit minimum rto per connection - cleanup sack scoreboard - switched svm fifo out-of-order data handling from absolute offsets to relative offsets. - improve cwnd handling when using sacks - add cc event debug stats - improved uri tcp test client/server: bugfixes and added half-duplex mode - expanded builtin client/server - updated uri socket client/server code to work in half-duplex - ensure session node unsets fifo event for empty fifo - fix session detach Change-Id: Ia446972340e32a65e0694ee2844355167d0c170d Signed-off-by: Florin Coras <fcoras@cisco.com>
Diffstat (limited to 'src/vnet/tcp/tcp_input.c')
-rw-r--r--src/vnet/tcp/tcp_input.c193
1 files changed, 110 insertions, 83 deletions
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index ff2229b3792..a2e6dad1298 100644
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -378,16 +378,20 @@ tcp_rcv_ack_is_acceptable (tcp_connection_t * tc0, vlib_buffer_t * tb0)
static void
tcp_estimate_rtt (tcp_connection_t * tc, u32 mrtt)
{
- int err;
+ int err, diff;
if (tc->srtt != 0)
{
err = mrtt - tc->srtt;
- tc->srtt += err >> 3;
+// tc->srtt += err >> 3;
/* XXX Drop in RTT results in RTTVAR increase and bigger RTO.
* The increase should be bound */
- tc->rttvar += ((int) clib_abs (err) - (int) tc->rttvar) >> 2;
+// tc->rttvar += ((int) clib_abs (err) - (int) tc->rttvar) >> 2;
+
+ tc->srtt = clib_max ((int) tc->srtt + (err >> 3), 1);
+ diff = (clib_abs (err) - (int) tc->rttvar) >> 2;
+ tc->rttvar = clib_max ((int) tc->rttvar + diff, 1);
}
else
{
@@ -401,6 +405,7 @@ void
tcp_update_rto (tcp_connection_t * tc)
{
tc->rto = clib_min (tc->srtt + (tc->rttvar << 2), TCP_RTO_MAX);
+ tc->rto = clib_max (tc->rto, TCP_RTO_MIN);
}
/** Update RTT estimate and RTO timer
@@ -417,8 +422,8 @@ tcp_update_rtt (tcp_connection_t * tc, u32 ack)
u32 mrtt = 0;
u8 rtx_acked;
- /* Determine if only rtx bytes are acked. TODO XXX fast retransmit */
- rtx_acked = tc->rto_boff && (tc->bytes_acked <= tc->snd_mss);
+ /* Determine if only rtx bytes are acked. */
+ rtx_acked = tcp_in_cong_recovery (tc) || !tc->bytes_acked;
/* Karn's rule, part 1. Don't use retransmitted segments to estimate
* RTT because they're ambiguous. */
@@ -428,8 +433,7 @@ tcp_update_rtt (tcp_connection_t * tc, u32 ack)
}
/* As per RFC7323 TSecr can be used for RTTM only if the segment advances
* snd_una, i.e., the left side of the send window:
- * seq_lt (tc->snd_una, ack). Note: last condition could be dropped, we don't
- * try to update rtt for dupacks */
+ * seq_lt (tc->snd_una, ack). */
else if (tcp_opts_tstamp (&tc->rcv_opts) && tc->rcv_opts.tsecr
&& tc->bytes_acked)
{
@@ -550,11 +554,13 @@ scoreboard_insert_hole (sack_scoreboard_t * sb, u32 prev_index,
prev = scoreboard_get_hole (sb, prev_index);
if (prev)
{
- hole->prev = prev - sb->holes;
+ hole->prev = prev_index;
hole->next = prev->next;
if ((next = scoreboard_next_hole (sb, hole)))
next->prev = hole_index;
+ else
+ sb->tail = hole_index;
prev->next = hole_index;
}
@@ -569,12 +575,13 @@ scoreboard_insert_hole (sack_scoreboard_t * sb, u32 prev_index,
}
void
-scoreboard_update_lost (tcp_connection_t * tc, sack_scoreboard_t * sb)
+scoreboard_update_bytes (tcp_connection_t * tc, sack_scoreboard_t * sb)
{
sack_scoreboard_hole_t *hole, *prev;
u32 bytes = 0, blks = 0;
sb->lost_bytes = 0;
+ sb->sacked_bytes = 0;
hole = scoreboard_last_hole (sb);
if (!hole)
return;
@@ -594,13 +601,16 @@ scoreboard_update_lost (tcp_connection_t * tc, sack_scoreboard_t * sb)
hole = prev;
}
- hole = prev;
while (hole)
{
sb->lost_bytes += scoreboard_hole_bytes (hole);
hole->is_lost = 1;
+ prev = hole;
hole = scoreboard_prev_hole (sb, hole);
+ if (hole)
+ bytes += prev->start - hole->end;
}
+ sb->sacked_bytes = bytes;
}
/**
@@ -677,7 +687,7 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
{
sack_scoreboard_t *sb = &tc->sack_sb;
sack_block_t *blk, tmp;
- sack_scoreboard_hole_t *hole, *next_hole, *last_hole, *new_hole;
+ sack_scoreboard_hole_t *hole, *next_hole, *last_hole;
u32 blk_index = 0, old_sacked_bytes, hole_index;
int i, j;
@@ -743,6 +753,10 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
if (seq_gt (tc->snd_una_max, sb->high_sacked)
&& seq_gt (tc->snd_una_max, last_hole->end))
last_hole->end = tc->snd_una_max;
+ /* keep track of max byte sacked for when the last hole
+ * is acked */
+ if (seq_gt (tmp.end, sb->high_sacked))
+ sb->high_sacked = tmp.end;
}
/* Walk the holes with the SACK blocks */
@@ -758,45 +772,20 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
{
next_hole = scoreboard_next_hole (sb, hole);
- /* Byte accounting */
- if (seq_leq (hole->end, ack))
- {
- /* Bytes lost because snd_wnd left edge advances */
- if (next_hole && seq_leq (next_hole->start, ack))
- sb->last_bytes_delivered += next_hole->start - hole->end;
- else
- sb->last_bytes_delivered += ack - hole->end;
- }
- else
- {
- sb->sacked_bytes += scoreboard_hole_bytes (hole);
- }
-
- /* About to remove last hole */
- if (hole == last_hole)
- {
- sb->tail = hole->prev;
- last_hole = scoreboard_last_hole (sb);
- /* keep track of max byte sacked for when the last hole
- * is acked */
- if (seq_gt (hole->end, sb->high_sacked))
- sb->high_sacked = hole->end;
- }
-
- /* snd_una needs to be advanced */
- if (blk->end == ack && seq_geq (ack, hole->end))
+ /* Byte accounting: snd_una needs to be advanced */
+ if (blk->end == ack)
{
- if (next_hole && seq_lt (ack, next_hole->start))
+ if (next_hole)
{
- sb->snd_una_adv = next_hole->start - ack;
-
- /* all these can be delivered */
- sb->last_bytes_delivered += sb->snd_una_adv;
+ if (seq_lt (ack, next_hole->start))
+ sb->snd_una_adv = next_hole->start - ack;
+ sb->last_bytes_delivered +=
+ next_hole->start - hole->end;
}
else if (!next_hole)
{
sb->snd_una_adv = sb->high_sacked - ack;
- sb->last_bytes_delivered += sb->snd_una_adv;
+ sb->last_bytes_delivered += sb->high_sacked - hole->end;
}
}
@@ -808,7 +797,6 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
{
if (seq_gt (blk->end, hole->start))
{
- sb->sacked_bytes += blk->end - hole->start;
hole->start = blk->end;
}
blk_index++;
@@ -819,28 +807,16 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
/* Hole must be split */
if (seq_lt (blk->end, hole->end))
{
- sb->sacked_bytes += blk->end - blk->start;
hole_index = scoreboard_hole_index (sb, hole);
- new_hole = scoreboard_insert_hole (sb, hole_index, blk->end,
- hole->end);
+ scoreboard_insert_hole (sb, hole_index, blk->end, hole->end);
/* Pool might've moved */
hole = scoreboard_get_hole (sb, hole_index);
hole->end = blk->start;
-
- /* New or split of tail */
- if ((last_hole->end == new_hole->end)
- || seq_lt (last_hole->end, new_hole->start))
- {
- last_hole = new_hole;
- sb->tail = scoreboard_hole_index (sb, new_hole);
- }
-
blk_index++;
}
- else if (seq_leq (blk->start, hole->end))
+ else if (seq_lt (blk->start, hole->end))
{
- sb->sacked_bytes += hole->end - blk->start;
hole->end = blk->start;
}
@@ -848,9 +824,13 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
}
}
- sb->last_sacked_bytes = sb->sacked_bytes - old_sacked_bytes;
- sb->sacked_bytes -= sb->last_bytes_delivered;
- scoreboard_update_lost (tc, sb);
+ scoreboard_update_bytes (tc, sb);
+ sb->last_sacked_bytes = sb->sacked_bytes
+ - (old_sacked_bytes - sb->last_bytes_delivered);
+ ASSERT (sb->sacked_bytes == 0
+ || sb->sacked_bytes < tc->snd_una_max - seq_max (tc->snd_una, ack));
+ ASSERT (sb->last_sacked_bytes + sb->lost_bytes <= tc->snd_una_max
+ - seq_max (tc->snd_una, ack));
}
/**
@@ -998,9 +978,14 @@ tcp_should_fastrecover (tcp_connection_t * tc)
|| tcp_should_fastrecover_sack (tc));
}
+/**
+ * One function to rule them all ... and in the darkness bind them
+ */
static void
tcp_cc_handle_event (tcp_connection_t * tc, u32 is_dack)
{
+ u32 rxt_delivered;
+
/*
* Duplicate ACK. Check if we should enter fast recovery, or if already in
* it account for the bytes that left the network.
@@ -1028,10 +1013,15 @@ tcp_cc_handle_event (tcp_connection_t * tc, u32 is_dack)
}
/* If of of the two conditions lower hold, reset dupacks
- * 1) Cumulative ack does not cover more than congestion threshold
+ * 1) Cumulative ack does not cover more than congestion threshold,
+ * and the following doesn't hold: the congestion window is
+ * greater than SMSS bytes and the difference between highest_ack
+ * and prev_highest_ack is at most 4*SMSS bytes (XXX)
* 2) RFC6582 heuristic to avoid multiple fast retransmits
*/
- if (seq_leq (tc->snd_una, tc->snd_congestion)
+ if ((seq_gt (tc->snd_una, tc->snd_congestion)
+ || !(tc->cwnd > tc->snd_mss
+ && tc->bytes_acked <= 4 * tc->snd_mss))
|| tc->rcv_opts.tsecr != tc->tsecr_last_ack)
{
tc->rcv_dupacks = 0;
@@ -1089,7 +1079,10 @@ partial_ack:
{
/* If spurious return, we've already updated everything */
if (tcp_cc_recover (tc))
- return;
+ {
+ tc->tsecr_last_ack = tc->rcv_opts.tsecr;
+ return;
+ }
tc->snd_nxt = tc->snd_una_max;
@@ -1115,12 +1108,16 @@ partial_ack:
return;
/* Remove retransmitted bytes that have been delivered */
- if (tc->sack_sb.last_bytes_delivered
- && seq_gt (tc->sack_sb.high_rxt, tc->snd_una))
+ ASSERT (tc->bytes_acked + tc->sack_sb.snd_una_adv
+ >= tc->sack_sb.last_bytes_delivered);
+ rxt_delivered = tc->bytes_acked + tc->sack_sb.snd_una_adv
+ - tc->sack_sb.last_bytes_delivered;
+ if (rxt_delivered && seq_gt (tc->sack_sb.high_rxt, tc->snd_una))
{
/* If we have sacks and we haven't gotten an ack beyond high_rxt,
* remove sacked bytes delivered */
- tc->snd_rxt_bytes -= tc->sack_sb.last_bytes_delivered;
+ ASSERT (tc->snd_rxt_bytes >= rxt_delivered);
+ tc->snd_rxt_bytes -= rxt_delivered;
}
else
{
@@ -1154,6 +1151,8 @@ tcp_rcv_ack (tcp_connection_t * tc, vlib_buffer_t * b,
u32 prev_snd_wnd, prev_snd_una;
u8 is_dack;
+ TCP_EVT_DBG (TCP_EVT_CC_STAT, tc);
+
/* If the ACK acks something not yet sent (SEG.ACK > SND.NXT) */
if (PREDICT_FALSE (seq_gt (vnet_buffer (b)->tcp.ack_number, tc->snd_nxt)))
{
@@ -1282,6 +1281,10 @@ tcp_update_sack_list (tcp_connection_t * tc, u32 start, u32 end)
{
vec_add1 (new_list, tc->snd_sacks[i]);
}
+ else
+ {
+ clib_warning ("sack discarded");
+ }
}
ASSERT (vec_len (new_list) <= TCP_MAX_SACK_BLOCKS);
@@ -1358,16 +1361,18 @@ tcp_session_enqueue_ooo (tcp_connection_t * tc, vlib_buffer_t * b,
stream_session_t *s0;
int rv;
+ ASSERT (seq_gt (vnet_buffer (b)->tcp.seq_number, tc->rcv_nxt));
+
/* Pure ACK. Do nothing */
if (PREDICT_FALSE (data_len == 0))
{
return TCP_ERROR_PURE_ACK;
}
- /* Enqueue out-of-order data with absolute offset */
+ /* Enqueue out-of-order data with relative offset */
rv = stream_session_enqueue_data (&tc->connection, b,
- vnet_buffer (b)->tcp.seq_number,
- 0 /* queue event */ , 0);
+ vnet_buffer (b)->tcp.seq_number -
+ tc->rcv_nxt, 0 /* queue event */ , 0);
/* Nothing written */
if (rv)
@@ -1388,10 +1393,15 @@ tcp_session_enqueue_ooo (tcp_connection_t * tc, vlib_buffer_t * b,
/* Get the newest segment from the fifo */
newest = svm_fifo_newest_ooo_segment (s0->server_rx_fifo);
- start = ooo_segment_offset (s0->server_rx_fifo, newest);
- end = ooo_segment_end_offset (s0->server_rx_fifo, newest);
+ if (newest)
+ {
+ start =
+ tc->rcv_nxt + ooo_segment_offset (s0->server_rx_fifo, newest);
+ end = start + ooo_segment_length (s0->server_rx_fifo, newest);
+ tcp_update_sack_list (tc, start, end);
- tcp_update_sack_list (tc, start, end);
+ ASSERT (seq_gt (start, tc->rcv_nxt));
+ }
}
return TCP_ERROR_ENQUEUED;
@@ -1411,7 +1421,7 @@ tcp_can_delack (tcp_connection_t * tc)
/* constrained to send ack */
|| (tc->flags & TCP_CONN_SNDACK) != 0
/* we're almost out of tx wnd */
- || tcp_available_snd_space (tc) < 2 * tc->snd_mss)
+ || tcp_available_snd_space (tc) < 4 * tc->snd_mss)
return 0;
return 1;
@@ -1434,7 +1444,7 @@ tcp_segment_rcv (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b,
*next0 = TCP_NEXT_DROP;
/* Completely in the past (possible retransmit) */
- if (seq_lt (vnet_buffer (b)->tcp.seq_end, tc->rcv_nxt))
+ if (seq_leq (vnet_buffer (b)->tcp.seq_end, tc->rcv_nxt))
goto done;
/* Chop off the bytes in the past */
@@ -1873,8 +1883,8 @@ tcp46_syn_sent_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
if (tcp_opts_wscale (&new_tc0->rcv_opts))
new_tc0->snd_wscale = new_tc0->rcv_opts.wscale;
- /* No scaling */
- new_tc0->snd_wnd = clib_net_to_host_u16 (tcp0->window);
+ new_tc0->snd_wnd = clib_net_to_host_u16 (tcp0->window)
+ << new_tc0->snd_wscale;
new_tc0->snd_wl1 = seq0;
new_tc0->snd_wl2 = ack0;
@@ -1892,8 +1902,15 @@ tcp46_syn_sent_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
/* Make sure las is initialized for the wnd computation */
new_tc0->rcv_las = new_tc0->rcv_nxt;
- /* Notify app that we have connection */
- stream_session_connect_notify (&new_tc0->connection, sst, 0);
+ /* Notify app that we have connection. If session layer can't
+ * allocate session send reset */
+ if (stream_session_connect_notify (&new_tc0->connection, sst,
+ 0))
+ {
+ tcp_connection_cleanup (new_tc0);
+ tcp_send_reset (b0, is_ip4);
+ goto drop;
+ }
stream_session_init_fifos_pointers (&new_tc0->connection,
new_tc0->irs + 1,
@@ -1907,7 +1924,14 @@ tcp46_syn_sent_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
new_tc0->state = TCP_STATE_SYN_RCVD;
/* Notify app that we have connection */
- stream_session_connect_notify (&new_tc0->connection, sst, 0);
+ if (stream_session_connect_notify
+ (&new_tc0->connection, sst, 0))
+ {
+ tcp_connection_cleanup (new_tc0);
+ tcp_send_reset (b0, is_ip4);
+ goto drop;
+ }
+
stream_session_init_fifos_pointers (&new_tc0->connection,
new_tc0->irs + 1,
new_tc0->iss + 1);
@@ -2508,8 +2532,8 @@ tcp46_listen_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
if (tcp_opts_wscale (&child0->rcv_opts))
child0->snd_wscale = child0->rcv_opts.wscale;
- /* No scaling */
- child0->snd_wnd = clib_net_to_host_u16 (th0->window);
+ child0->snd_wnd = clib_net_to_host_u16 (th0->window)
+ << child0->snd_wscale;
child0->snd_wl1 = vnet_buffer (b0)->tcp.seq_number;
child0->snd_wl2 = vnet_buffer (b0)->tcp.ack_number;
@@ -2892,6 +2916,9 @@ do { \
_(FIN_WAIT_2, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(FIN_WAIT_2, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,
TCP_ERROR_NONE);
+ _(CLOSE_WAIT, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
+ _(CLOSE_WAIT, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,
+ TCP_ERROR_NONE);
_(LAST_ACK, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(LAST_ACK, TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(LAST_ACK, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,