From 750ea2bafa55aaed208b2583470ecd7122225634 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Wed, 2 May 2012 13:30:04 +0000 Subject: tcp: early retransmit: delayed fast retransmit Implementing the advanced early retransmit (sysctl_tcp_early_retrans==2). Delays the fast retransmit by an interval of RTT/4. We borrow the RTO timer to implement the delay. If we receive another ACK or send a new packet, the timer is cancelled and restored to original RTO value offset by time elapsed. When the delayed-ER timer fires, we enter fast recovery and perform fast retransmit. Signed-off-by: Yuchung Cheng Acked-by: Neal Cardwell Signed-off-by: David S. Miller --- net/ipv4/tcp_timer.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'net/ipv4/tcp_timer.c') diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 34d4a02c2f16..e911e6c523ec 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -319,6 +319,11 @@ void tcp_retransmit_timer(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk); + if (tp->early_retrans_delayed) { + tcp_resume_early_retransmit(sk); + return; + } + if (!tp->packets_out) goto out; -- cgit v1.2.3-59-g8ed1b