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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-09-22 20:02:19 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-09-27 00:58:44 -0400 |
| commit | 7a269ffad72f3604b8982fa09c387670e0d2ee14 (patch) | |
| tree | 3655a22066bcb1011e5e1b717a00a108143dfd85 /include/net/tcp.h | |
| parent | 0bdb0bd0139f3b6afa252de1487e3ce82a494db9 (diff) | |
| download | lwn-7a269ffad72f3604b8982fa09c387670e0d2ee14.tar.gz lwn-7a269ffad72f3604b8982fa09c387670e0d2ee14.zip | |
tcp: ECN blackhole should not force quickack mode
While playing with a new ADSL box at home, I discovered that ECN
blackhole can trigger suboptimal quickack mode on linux : We send one
ACK for each incoming data frame, without any delay and eventual
piggyback.
This is because TCP_ECN_check_ce() considers that if no ECT is seen on a
segment, this is because this segment was a retransmit.
Refine this heuristic and apply it only if we seen ECT in a previous
segment, to detect ECN blackhole at IP level.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Jamal Hadi Salim <jhs@mojatatu.com>
CC: Jerry Chu <hkchu@google.com>
CC: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
CC: Jim Gettys <jg@freedesktop.org>
CC: Dave Taht <dave.taht@gmail.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/tcp.h')
| -rw-r--r-- | include/net/tcp.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index f357befaaa01..702aefc8d43d 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -356,6 +356,7 @@ static inline void tcp_dec_quickack_mode(struct sock *sk, #define TCP_ECN_OK 1 #define TCP_ECN_QUEUE_CWR 2 #define TCP_ECN_DEMAND_CWR 4 +#define TCP_ECN_SEEN 8 static __inline__ void TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th) |