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| author | Eric Dumazet <edumazet@google.com> | 2015-02-26 14:10:20 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-02-28 15:10:39 -0500 |
| commit | a0ea700e4095e26a8e291374757dd29519900f18 (patch) | |
| tree | 5dc19465848a991d8baf2ac3cac3079c92baef5f | |
| parent | 50c8339e9299aaf09e48c8f94de39baec638c874 (diff) | |
| download | linux-a0ea700e4095e26a8e291374757dd29519900f18.tar.gz linux-a0ea700e4095e26a8e291374757dd29519900f18.tar.bz2 linux-a0ea700e4095e26a8e291374757dd29519900f18.zip | |
tcp: tso: allow CA_CWR state in tcp_tso_should_defer()
Another TCP issue is triggered by ECN.
Under pressure, receiver gets ECN marks, and send back ACK packets
with ECE TCP flag. Senders enter CA_CWR state.
In this state, tcp_tso_should_defer() is short cut :
if (icsk->icsk_ca_state != TCP_CA_Open)
goto send_now;
This means that about all ACK packets we receive are triggering
a partial send, and because cwnd is kept small, we can only send
a small amount of data for each incoming ACK,
which in return generate more ACK packets.
Allowing CA_Open and CA_CWR states to enable TSO defer in
tcp_tso_should_defer() brings performance back :
TSO autodefer has more chance to defer under pressure.
This patch increases TSO and LRO/GRO efficiency back to normal levels,
and does not impact overall ECN behavior.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/tcp_output.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 5f4fb4d5bbd6..8bbd86cd81c8 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1762,7 +1762,7 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb, if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) goto send_now; - if (icsk->icsk_ca_state != TCP_CA_Open) + if (!((1 << icsk->icsk_ca_state) & (TCPF_CA_Open | TCPF_CA_CWR))) goto send_now; /* Avoid bursty behavior by allowing defer |