> On Tue, 2015-07-07 at 14:22 +1000, Jon Maxwell wrote:
>
>
> > @@ -4887,6 +4884,7 @@ static inline void tcp_data_snd_check(struct sock
> > *sk)
> > static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible)
> > {
> > struct tcp_sock *tp = tcp_sk(sk);
> > + const struct dst_entry *dst = __sk_dst_get(sk);
> >
> > /* More than one full frame received... */
> > if (((tp->rcv_nxt - tp->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss &&
> > @@ -4896,6 +4894,8 @@ static void __tcp_ack_snd_check(struct sock *sk, int
> > ofo_possible)
> > __tcp_select_window(sk) >= tp->rcv_wnd) ||
> > /* We ACK each frame or... */
> > tcp_in_quickack_mode(sk) ||
> > + /* quickack on dst */
> > + (dst && dst_metric(dst, RTAX_QUICKACK)) ||
> > /* We have out of order data. */
> > (ofo_possible && skb_peek(&tp->out_of_order_queue))) {
>
> This logic should be moved to tcp_in_quickack_mode() ?
Yes agreed that's a better place for the check seeing that we
already check the other quickack conditions there as well.
>
> Note I placed the dst test before others, to reduce jump prediction
> misses.
>
> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
> index 684f095d196e..69ec8d25a2e5 100644
> --- a/net/ipv4/tcp_input.c
> +++ b/net/ipv4/tcp_input.c
> @@ -196,11 +196,13 @@ static void tcp_enter_quickack_mode(struct sock *sk)
> * and the session is not interactive.
> */
>
> -static inline bool tcp_in_quickack_mode(const struct sock *sk)
> +static bool tcp_in_quickack_mode(struct sock *sk)
> {
> const struct inet_connection_sock *icsk = inet_csk(sk);
> + const struct dst_entry *dst = __sk_dst_get(sk);
>
> - return icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong;
> + return (dst && dst_metric(dst, RTAX_QUICKACK)) ||
> + (icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong);
> }
>
> static void tcp_ecn_queue_cwr(struct tcp_sock *tp)
>
>
On Tue, Jul 7, 2015 at 5:05 PM, Eric Dumazet <eric.duma...@gmail.com> wrote:
> On Tue, 2015-07-07 at 14:22 +1000, Jon Maxwell wrote:
>
>
>> @@ -4887,6 +4884,7 @@ static inline void tcp_data_snd_check(struct sock *sk)
>> static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible)
>> {
>> struct tcp_sock *tp = tcp_sk(sk);
>> + const struct dst_entry *dst = __sk_dst_get(sk);
>>
>> /* More than one full frame received... */
>> if (((tp->rcv_nxt - tp->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss &&
>> @@ -4896,6 +4894,8 @@ static void __tcp_ack_snd_check(struct sock *sk, int
>> ofo_possible)
>> __tcp_select_window(sk) >= tp->rcv_wnd) ||
>> /* We ACK each frame or... */
>> tcp_in_quickack_mode(sk) ||
>> + /* quickack on dst */
>> + (dst && dst_metric(dst, RTAX_QUICKACK)) ||
>> /* We have out of order data. */
>> (ofo_possible && skb_peek(&tp->out_of_order_queue))) {
>
> This logic should be moved to tcp_in_quickack_mode() ?
>
> Note I placed the dst test before others, to reduce jump prediction
> misses.
>
> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
> index 684f095d196e..69ec8d25a2e5 100644
> --- a/net/ipv4/tcp_input.c
> +++ b/net/ipv4/tcp_input.c
> @@ -196,11 +196,13 @@ static void tcp_enter_quickack_mode(struct sock *sk)
> * and the session is not interactive.
> */
>
> -static inline bool tcp_in_quickack_mode(const struct sock *sk)
> +static bool tcp_in_quickack_mode(struct sock *sk)
> {
> const struct inet_connection_sock *icsk = inet_csk(sk);
> + const struct dst_entry *dst = __sk_dst_get(sk);
>
> - return icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong;
> + return (dst && dst_metric(dst, RTAX_QUICKACK)) ||
> + (icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong);
> }
>
> static void tcp_ecn_queue_cwr(struct tcp_sock *tp)
>
>
>
>
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