diff options
| author |   Florin Coras <fcoras@cisco.com> | 2019-09-11 13:42:57 -0700 |
|---|---|---|
| committer |   Andrew Yourtchenko <ayourtch@gmail.com> | 2019-09-29 16:45:32 +0000 |
| commit | 6702641f536ba1a14075b2b24ffd2fb9c6167791 (patch) | |
| tree | 948ba872a335926b9731e182399a6d76afbd0b09 | |
| parent | dedb3c8d95322cbac280660bc21665b35d8a3af1 (diff) | |
tcp: use rate sample rtt in recovery if possible
If in recovery and rate samples are taken for burts that have not been
retransmitted, use the rtt estimate.
Type: feature
Change-Id: I95028f492008457c959157aa4ee4c3435fa9c3f0
Signed-off-by: Florin Coras <fcoras@cisco.com>
(cherry picked from commit 1dbda64b467f020db131cb9a01422b8f3fbf58df)
| -rwxr-xr-x | src/vnet/tcp/tcp_input.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c index f4e1026e4c5..ad937e90438 100755 --- a/src/vnet/tcp/tcp_input.c +++ b/src/vnet/tcp/tcp_input.c @@ -494,14 +494,20 @@ tcp_update_rto (tcp_connection_t * tc) * return 1 if valid rtt 0 otherwise */ static int -tcp_update_rtt (tcp_connection_t * tc, u32 ack) +tcp_update_rtt (tcp_connection_t * tc, tcp_rate_sample_t * rs, u32 ack) { u32 mrtt = 0; /* Karn's rule, part 1. Don't use retransmitted segments to estimate * RTT because they're ambiguous. */ - if (tcp_in_cong_recovery (tc) || tc->sack_sb.sacked_bytes) + if (tcp_in_cong_recovery (tc)) { + /* Accept rtt estimates for samples that have not been retransmitted */ + if ((tc->flags & TCP_CONN_RATE_SAMPLE) && !(rs->flags & TCP_BTS_IS_RXT)) + { + mrtt = rs->rtt_time * THZ; + goto estimate_rtt; + } if (tcp_in_recovery (tc)) return 0; goto done; @@ -524,6 +530,8 @@ tcp_update_rtt (tcp_connection_t * tc, u32 ack) mrtt = clib_max (now - tc->rcv_opts.tsecr, 1); } +estimate_rtt: + /* Ignore dubious measurements */ if (mrtt == 0 || mrtt > TCP_RTT_MAX) goto done; @@ -1601,15 +1609,15 @@ process_ack: tc->snd_una = vnet_buffer (b)->tcp.ack_number; tcp_validate_txf_size (tc, tc->bytes_acked); + if (tc->flags & TCP_CONN_RATE_SAMPLE) + tcp_bt_sample_delivery_rate (tc, &rs); + if (tc->bytes_acked) { tcp_program_dequeue (wrk, tc); - tcp_update_rtt (tc, vnet_buffer (b)->tcp.ack_number); + tcp_update_rtt (tc, &rs, vnet_buffer (b)->tcp.ack_number); } - if (tc->flags & TCP_CONN_RATE_SAMPLE) - tcp_bt_sample_delivery_rate (tc, &rs); - TCP_EVT (TCP_EVT_ACK_RCVD, tc); /* |