From 85fc13004df7f67012a04e73564ecef1b3641ef3 Mon Sep 17 00:00:00 2001 From: Florin Coras Date: Wed, 26 Jun 2019 09:12:34 -0700 Subject: [PATCH] tcp: improve rate estimate Type:feature - sample rtt estimation - report acked+sacked - report last lost bytes - use snd_una == snd_nxt to detect 0 bytes in flight Change-Id: I83181261fdb375c7e33d24b7a82343561e6a905f Signed-off-by: Florin Coras --- src/plugins/unittest/tcp_test.c | 23 +++++++++++++---------- src/vnet/tcp/tcp.h | 14 ++++++++++---- src/vnet/tcp/tcp_bt.c | 17 ++++++++++++----- 3 files changed, 35 insertions(+), 19 deletions(-) diff --git a/src/plugins/unittest/tcp_test.c b/src/plugins/unittest/tcp_test.c index 7d0d229f3ca..6f765e7a4fc 100644 --- a/src/plugins/unittest/tcp_test.c +++ b/src/plugins/unittest/tcp_test.c @@ -857,9 +857,9 @@ tcp_test_delivery (vlib_main_t * vm, unformat_input_t * input) TCP_TEST (pool_elts (bt->samples) == 0, "sample should've been consumed"); TCP_TEST (tc->delivered_time == 2, "delivered time should be 2"); TCP_TEST (tc->delivered == burst, "delivered should be 100"); - TCP_TEST (rs->ack_time == 1, "ack time should be 1"); + TCP_TEST (rs->interval_time == 1, "ack time should be 1"); TCP_TEST (rs->delivered == burst, "delivered should be 100"); - TCP_TEST (rs->sample_delivered == 0, "sample delivered should be 0"); + TCP_TEST (rs->prior_delivered == 0, "sample delivered should be 0"); TCP_TEST (approx_equal (rate, rs->tx_rate), "rate should be %u is %u", rate, rs->tx_rate); TCP_TEST (!(rs->flags & TCP_BTS_IS_RXT), "not retransmitted"); @@ -897,9 +897,9 @@ tcp_test_delivery (vlib_main_t * vm, unformat_input_t * input) TCP_TEST (tc->delivered_time == 4, "delivered time should be 4"); TCP_TEST (tc->delivered == 3 * burst, "delivered should be 300 is %u", tc->delivered); - TCP_TEST (rs->ack_time == 2, "ack time should be 2"); + TCP_TEST (rs->interval_time == 2, "ack time should be 2"); TCP_TEST (rs->delivered == 2 * burst, "delivered should be 200"); - TCP_TEST (rs->sample_delivered == burst, "delivered should be 100"); + TCP_TEST (rs->prior_delivered == burst, "delivered should be 100"); TCP_TEST (approx_equal (rate, rs->tx_rate), "rate should be %u is %u", rate, rs->tx_rate); TCP_TEST (!(rs->flags & TCP_BTS_IS_RXT), "not retransmitted"); @@ -964,9 +964,10 @@ tcp_test_delivery (vlib_main_t * vm, unformat_input_t * input) 3 * burst + 30, tc->delivered); /* All 3 samples have the same delivered number of bytes. So the first is * the reference for delivery estimate. */ - TCP_TEST (rs->ack_time == 4, "ack time should be 4 is %.2f", rs->ack_time); + TCP_TEST (rs->interval_time == 4, "ack time should be 4 is %.2f", + rs->interval_time); TCP_TEST (rs->delivered == 30, "delivered should be 30"); - TCP_TEST (rs->sample_delivered == 3 * burst, + TCP_TEST (rs->prior_delivered == 3 * burst, "sample delivered should be %u", 3 * burst); TCP_TEST (approx_equal (rate, rs->tx_rate), "rate should be %u is %u", rate, rs->tx_rate); @@ -1045,11 +1046,12 @@ tcp_test_delivery (vlib_main_t * vm, unformat_input_t * input) TCP_TEST (tc->delivered == 5 * burst + 40, "delivered should be %u is %u", 5 * burst + 40, tc->delivered); /* A rxt was acked and delivered time for it is 8 (last ack time) */ - TCP_TEST (rs->ack_time == 2, "ack time should be 2 is %.2f", rs->ack_time); + TCP_TEST (rs->interval_time == 2, "ack time should be 2 is %.2f", + rs->interval_time); /* delivered_now - delivered_rxt ~ 5 * burst + 40 - 3 * burst - 30 */ TCP_TEST (rs->delivered == 2 * burst + 10, "delivered should be 210 is %u", rs->delivered); - TCP_TEST (rs->sample_delivered == 3 * burst + 30, + TCP_TEST (rs->prior_delivered == 3 * burst + 30, "sample delivered should be %u", 3 * burst + 30); TCP_TEST (approx_equal (rate, rs->tx_rate), "rate should be %u is %u", rate, rs->tx_rate); @@ -1077,12 +1079,13 @@ tcp_test_delivery (vlib_main_t * vm, unformat_input_t * input) TCP_TEST (tc->delivered == 7 * burst, "delivered should be %u is %u", 7 * burst, tc->delivered); /* Last rxt was at time 8 */ - TCP_TEST (rs->ack_time == 3, "ack time should be 3 is %.2f", rs->ack_time); + TCP_TEST (rs->interval_time == 3, "ack time should be 3 is %.2f", + rs->interval_time); /* delivered_now - delivered_rxt ~ 7 * burst - 3 * burst - 30. * That's because we didn't retransmit any new segment. */ TCP_TEST (rs->delivered == 4 * burst - 30, "delivered should be 160 is %u", rs->delivered); - TCP_TEST (rs->sample_delivered == 3 * burst + 30, + TCP_TEST (rs->prior_delivered == 3 * burst + 30, "sample delivered should be %u", 3 * burst + 30); TCP_TEST (approx_equal (rate, rs->tx_rate), "rate should be %u is %u", rate, rs->tx_rate); diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h index d736685771d..7ccc06aea9c 100644 --- a/src/vnet/tcp/tcp.h +++ b/src/vnet/tcp/tcp.h @@ -249,18 +249,24 @@ typedef struct tcp_bt_sample_ u32 prev; /**< Previous sample index in list */ u32 min_seq; /**< Min seq number in sample */ u32 max_seq; /**< Max seq number. Set for rxt samples */ - u64 delivered; /**< Total delivered when sample taken */ + u64 delivered; /**< Total delivered bytes for sample */ f64 delivered_time; /**< Delivered time when sample taken */ + f64 tx_time; /**< Transmit time for the burst */ u64 tx_rate; /**< Tx pacing rate */ tcp_bts_flags_t flags; /**< Sample flag */ } tcp_bt_sample_t; typedef struct tcp_rate_sample_ { - u64 sample_delivered; /**< Delivered of sample used for rate */ - u32 delivered; /**< Bytes delivered in ack time */ - f64 ack_time; /**< Time to ack the bytes delivered */ + u64 prior_delivered; /**< Delivered of sample used for rate, i.e., + total bytes delivered at prior_time */ + f64 prior_time; /**< Delivered time of sample used for rate */ + f64 interval_time; /**< Time to ack the bytes delivered */ + f64 rtt_time; /**< RTT for sample */ u64 tx_rate; /**< Tx pacing rate */ + u32 delivered; /**< Bytes delivered in interval_time */ + u32 acked_and_sacked; /**< Bytes acked + sacked now */ + u32 lost; /**< Bytes lost now */ tcp_bts_flags_t flags; /**< Rate sample flags from bt sample */ } tcp_rate_sample_t; diff --git a/src/vnet/tcp/tcp_bt.c b/src/vnet/tcp/tcp_bt.c index 74947474b53..dd3d9539d9a 100644 --- a/src/vnet/tcp/tcp_bt.c +++ b/src/vnet/tcp/tcp_bt.c @@ -242,6 +242,7 @@ tcp_bt_alloc_tx_sample (tcp_connection_t * tc, u32 min_seq) bts->delivered = tc->delivered; bts->delivered_time = tc->delivered_time; bts->tx_rate = transport_connection_tx_pacer_rate (&tc->connection); + bts->tx_time = tcp_time_now_us (tc->c_thread_index); bts->flags |= tc->app_limited ? TCP_BTS_IS_APP_LIMITED : 0; return bts; } @@ -268,7 +269,7 @@ tcp_bt_track_tx (tcp_connection_t * tc) tcp_bt_sample_t *bts, *tail; u32 bts_index; - if (!tcp_flight_size (tc)) + if (tc->snd_una == tc->snd_nxt) tc->delivered_time = tcp_time_now_us (tc->c_thread_index); bts = tcp_bt_alloc_tx_sample (tc, tc->snd_nxt); @@ -415,12 +416,12 @@ static void tcp_bt_sample_to_rate_sample (tcp_connection_t * tc, tcp_bt_sample_t * bts, tcp_rate_sample_t * rs) { - if (rs->sample_delivered && rs->sample_delivered >= bts->delivered) + if (rs->prior_delivered && rs->prior_delivered >= bts->delivered) return; - rs->sample_delivered = bts->delivered; - rs->delivered = tc->delivered - bts->delivered; - rs->ack_time = tc->delivered_time - bts->delivered_time; + rs->prior_delivered = bts->delivered; + rs->prior_time = bts->delivered_time; + rs->rtt_time = bts->tx_time; rs->tx_rate = bts->tx_rate; rs->flags = bts->flags; } @@ -527,6 +528,12 @@ tcp_bt_sample_delivery_rate (tcp_connection_t * tc, tcp_rate_sample_t * rs) if (tc->sack_sb.last_sacked_bytes) tcp_bt_walk_samples_ooo (tc, rs); + + rs->interval_time = tc->delivered_time - rs->prior_time; + rs->delivered = tc->delivered - rs->prior_delivered; + rs->rtt_time = tc->delivered_time - rs->rtt_time; + rs->acked_and_sacked = delivered; + rs->lost = tc->sack_sb.last_lost_bytes; } void -- 2.16.6