GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-07-23 23:32:14 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

tcp: use sequence to break TS ties for RACK loss detection

Browse source 
The packets inside a jumbo skb (e.g., TSO) share the same skb
timestamp, even though they are sent sequentially on the wire. Since
RACK is based on time, it can not detect some packets inside the
same skb are lost.  However, we can leverage the packet sequence
numbers as extended timestamps to detect losses. Therefore, when
RACK timestamp is identical to skb's timestamp (i.e., one of the
packets of the skb is acked or sacked), we use the sequence numbers
of the acked and unacked packets to break ties.

We can use the same sequence logic to advance RACK xmit time as
well to detect more losses and avoid timeout.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yuchung Cheng 2017-01-12 22:11:34 -08:00 • committed by David S. Miller
parent 57dde7f70d
commit 1d0833df59
4 changed files with 19 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

5
net/ipv4/tcp_input.c
View file

@ -1218,7 +1218,8 @@ static u8 tcp_sacktag_one(struct sock *sk,
return sacked;
if (!(sacked & TCPCB_SACKED_ACKED)) {
tcp_rack_advance(tp, sacked, xmit_time, &state->ack_time);
tcp_rack_advance(tp, sacked, end_seq,
xmit_time, &state->ack_time);
if (sacked & TCPCB_SACKED_RETRANS) {
/* If the segment is not tagged as lost,
@ -3171,7 +3172,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
} else if (tcp_is_sack(tp)) {
tp->delivered += acked_pcount;
if (!tcp_skb_spurious_retrans(tp, skb))
tcp_rack_advance(tp, sacked,
tcp_rack_advance(tp, sacked, scb->end_seq,
&skb->skb_mstamp,
&sack->ack_time);
}