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authorFlorin Coras <fcoras@cisco.com>2019-09-11 23:22:29 -0700
committerDave Barach <openvpp@barachs.net>2019-09-20 15:57:14 +0000
commitafef8bf22369d10ab8107a63b1e3529ed7dd6c8d (patch)
treec398f5e28d890dfd80b8f473f22a8ddc8af70928
parent9137e5400699bed9f7c0095187839a8b38273100 (diff)
tcp: refactor congestion event handling
Type: refactor Minor cleanup to congestion event handling. Change-Id: I7179ff9e21c1853382ba814652c9024f3e5b8a37 Signed-off-by: Florin Coras <fcoras@cisco.com>
-rwxr-xr-xsrc/vnet/tcp/tcp_input.c76
1 files changed, 36 insertions, 40 deletions
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index ad937e90438..933f913bc5a 100755
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -614,10 +614,8 @@ tcp_handle_postponed_dequeues (tcp_worker_ctx_t * wrk)
* otherwise update. */
tcp_retransmit_timer_update (tc);
- /* If not congested, update pacer based on our new
- * cwnd estimate */
- if (!tcp_in_fastrecovery (tc))
- tcp_connection_tx_pacer_update (tc);
+ /* Update pacer based on our new cwnd estimate */
+ tcp_connection_tx_pacer_update (tc);
}
_vec_len (wrk->pending_deq_acked) = 0;
}
@@ -1375,34 +1373,46 @@ static void
tcp_cc_handle_event (tcp_connection_t * tc, tcp_rate_sample_t * rs,
u32 is_dack)
{
- u32 rxt_delivered;
+ u8 has_sack = tcp_opts_sack_permitted (&tc->rcv_opts);
- if (tcp_in_fastrecovery (tc) && tcp_opts_sack_permitted (&tc->rcv_opts))
+ /*
+ * Already in fast recovery. Return if no data acked, partial acks
+ * and accounting for segments that have left the network are done
+ * lower.
+ */
+ if (tcp_in_fastrecovery (tc))
{
- if (tc->bytes_acked)
- goto partial_ack;
- tcp_program_fastretransmit (tc);
- return;
+ if (!has_sack)
+ tc->rcv_dupacks++;
+
+ if (!tc->bytes_acked)
+ {
+ tcp_program_fastretransmit (tc);
+ if (!has_sack)
+ tcp_cc_rcv_cong_ack (tc, TCP_CC_DUPACK, rs);
+ return;
+ }
+ }
+ /*
+ * In timer triggered recovery
+ */
+ else if (tcp_in_recovery (tc))
+ {
+ /* No fast recovery entry at this point */
+ if (!tc->bytes_acked)
+ return;
}
/*
- * Duplicate ACK. Check if we should enter fast recovery, or if already in
- * it account for the bytes that left the network.
+ * Duplicate ACK. Check if we should enter fast recovery
*/
- else if (is_dack && !tcp_in_recovery (tc))
+ else if (is_dack)
{
TCP_EVT (TCP_EVT_DUPACK_RCVD, tc, 1);
ASSERT (tc->snd_una != tc->snd_nxt || tc->sack_sb.last_sacked_bytes);
tc->rcv_dupacks++;
- /* Pure duplicate ack. If some data got acked, it's handled lower */
- if (tc->rcv_dupacks > TCP_DUPACK_THRESHOLD && !tc->bytes_acked)
- {
- ASSERT (tcp_in_fastrecovery (tc));
- tcp_cc_rcv_cong_ack (tc, TCP_CC_DUPACK, rs);
- return;
- }
- else if (tcp_should_fastrecover (tc))
+ if (tcp_should_fastrecover (tc))
{
u32 pacer_wnd;
@@ -1419,7 +1429,7 @@ tcp_cc_handle_event (tcp_connection_t * tc, tcp_rate_sample_t * rs,
tcp_cc_init_congestion (tc);
- if (tcp_opts_sack_permitted (&tc->rcv_opts))
+ if (has_sack)
scoreboard_init_high_rxt (&tc->sack_sb, tc->snd_una);
/* Constrain rate until we get a partial ack */
@@ -1429,14 +1439,11 @@ tcp_cc_handle_event (tcp_connection_t * tc, tcp_rate_sample_t * rs,
tcp_program_fastretransmit (tc);
return;
}
- else if (!tc->bytes_acked
- || (tc->bytes_acked && !tcp_in_cong_recovery (tc)))
+ else
{
tcp_cc_rcv_cong_ack (tc, TCP_CC_DUPACK, rs);
return;
}
- else
- goto partial_ack;
}
/* Don't allow entry in fast recovery if still in recovery, for now */
else if (0 && is_dack && tcp_in_recovery (tc))
@@ -1461,24 +1468,15 @@ tcp_cc_handle_event (tcp_connection_t * tc, tcp_rate_sample_t * rs,
}
}
- if (!tc->bytes_acked)
- return;
-
-partial_ack:
+ ASSERT (tc->bytes_acked);
TCP_EVT (TCP_EVT_CC_PACK, tc);
/*
* Legitimate ACK. 1) See if we can exit recovery
*/
- /* Update the pacing rate. For the first partial ack we move from
- * the artificially constrained rate to the one after congestion */
- tcp_connection_tx_pacer_update (tc);
-
if (seq_geq (tc->snd_una, tc->snd_congestion))
{
- tcp_retransmit_timer_update (tc);
-
/* If spurious return, we've already updated everything */
if (tcp_cc_recover (tc))
{
@@ -1495,9 +1493,6 @@ partial_ack:
* Legitimate ACK. 2) If PARTIAL ACK try to retransmit
*/
- /* XXX limit this only to first partial ack? */
- tcp_retransmit_timer_update (tc);
-
/* RFC6675: If the incoming ACK is a cumulative acknowledgment,
* reset dupacks to 0. Also needed if in congestion recovery */
tc->rcv_dupacks = 0;
@@ -1511,7 +1506,7 @@ partial_ack:
}
/* Remove retransmitted bytes that have been delivered */
- if (tcp_opts_sack_permitted (&tc->rcv_opts))
+ if (has_sack)
{
ASSERT (tc->bytes_acked >= tc->sack_sb.last_bytes_delivered
|| (tc->flags & TCP_CONN_FINSNT));
@@ -1520,6 +1515,7 @@ partial_ack:
* remove sacked bytes delivered */
if (seq_lt (tc->snd_una, tc->sack_sb.high_rxt))
{
+ u32 rxt_delivered;
rxt_delivered = tc->bytes_acked - tc->sack_sb.last_bytes_delivered;
ASSERT (tc->snd_rxt_bytes >= rxt_delivered);
tc->snd_rxt_bytes -= rxt_delivered;