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Date: Mon, 24 Nov 2008 16:22:04 +0200 From: "Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi> To: David Miller <davem@...emloft.net> Cc: netdev@...r.kernel.org, "Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi> Subject: [PATCH 07/10] tcp: Make shifting not clear the hints The earlier version was just very basic one which is "playing safe" by always clearing the hints. However, clearing of a hint is extremely costly operation with large windows, so it must be avoided at all cost whenever possible, there is a way with shifting too achieve not-clearing. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...sinki.fi> --- net/ipv4/tcp_input.c | 16 ++++++++++++++-- 1 files changed, 14 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 8106421..1f73cda 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1378,6 +1378,11 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *prev, BUG_ON(!pcount); + /* Tweak before seqno plays */ + if (!tcp_is_fack(tp) && tcp_is_sack(tp) && tp->lost_skb_hint && + !before(TCP_SKB_CB(tp->lost_skb_hint)->seq, TCP_SKB_CB(skb)->seq)) + tp->lost_cnt_hint += pcount; + TCP_SKB_CB(prev)->end_seq += shifted; TCP_SKB_CB(skb)->seq += shifted; @@ -1407,8 +1412,6 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *prev, /* Difference in this won't matter, both ACKed by the same cumul. ACK */ TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS); - tcp_clear_all_retrans_hints(tp); - if (skb->len > 0) { BUG_ON(!tcp_skb_pcount(skb)); return 0; @@ -1416,6 +1419,15 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *prev, /* Whole SKB was eaten :-) */ + if (skb == tp->retransmit_skb_hint) + tp->retransmit_skb_hint = prev; + if (skb == tp->scoreboard_skb_hint) + tp->scoreboard_skb_hint = prev; + if (skb == tp->lost_skb_hint) { + tp->lost_skb_hint = prev; + tp->lost_cnt_hint -= tcp_skb_pcount(prev); + } + TCP_SKB_CB(skb)->flags |= TCP_SKB_CB(prev)->flags; if (skb == tcp_highest_sack(sk)) tcp_advance_highest_sack(sk, skb); -- 1.5.2.2 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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