From 932eb7638ad7d9145620178992044b5e87356969 Mon Sep 17 00:00:00 2001 From: Kenneth Klette Jonassen Date: Thu, 29 Jan 2015 20:08:03 +0100 Subject: [PATCH] tcp: use SACK RTTs for CC Current behavior only passes RTTs from sequentially acked data to CC. If sender gets a combined ACK for segment 1 and SACK for segment 3, then the computed RTT for CC is the time between sending segment 1 and receiving SACK for segment 3. Pass the minimum computed RTT from any acked data to CC, i.e. time between sending segment 3 and receiving SACK for segment 3. Signed-off-by: Kenneth Klette Jonassen Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 71fb37c70581..ed11931f340f 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3183,8 +3183,10 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, tp->fackets_out -= min(pkts_acked, tp->fackets_out); - if (ca_ops->pkts_acked) - ca_ops->pkts_acked(sk, pkts_acked, ca_seq_rtt_us); + if (ca_ops->pkts_acked) { + long rtt_us = min_t(ulong, ca_seq_rtt_us, sack_rtt_us); + ca_ops->pkts_acked(sk, pkts_acked, rtt_us); + } } else if (skb && rtt_update && sack_rtt_us >= 0 && sack_rtt_us > skb_mstamp_us_delta(&now, &skb->skb_mstamp)) {