On Fri, 21 Dec 2007, Gavin McCullagh wrote:
> On Fri, 21 Dec 2007, David Miller wrote:
>
> > When Gavin respins the patch I'll look at in the context of submitting
> > it as a bug fix. So Gavin please generate the patch against Linus's
> > vanilla GIT tree or net-2.6, your choise.
>
> The existing patch was against Linus' linux-2.6.git from a few days ago so
> I've updated my tree and regenerated the patch (below). Is that the right
> one?
>
> I'm just checking through the existing CA modules. I don't see the rtt
> used for RTO anywhere. This is what I gather they're each using rtt for.
I meant more timeout like fashion (e.g., to "timeout" some internal
phase but I don't find that too likely)...
Thanks for checking them.
> So as far as I can tell, timeout stuff is not ever altered using
> pkts_acked() so I guess this fix only affects westwood, htcp and cubic just
> now.
>
> I need to re-read properly, but I think the same problem affects the
> microsecond values where TCP_CONG_RTT_STAMP is set (used by vegas, veno,
> yeah, illinois). I might follow up with another patch which changes the
> behaviour where TCP_CONG_RTT_STAMP when I'm more sure of that.
Please do, you might have to remove fully_acked checks to do that right
though so it won't be as straight-forward change as this one and requires
some amount of thinking to result in a right thing.
> Signed-off-by: Gavin McCullagh <[EMAIL PROTECTED]>
>
> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
> index 889c893..6fb7989 100644
> --- a/net/ipv4/tcp_input.c
> +++ b/net/ipv4/tcp_input.c
> @@ -2651,6 +2651,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, s32
> *seq_rtt_p,
> u32 cnt = 0;
> u32 reord = tp->packets_out;
> s32 seq_rtt = -1;
> + s32 ca_seq_rtt = -1;
> ktime_t last_ackt = net_invalid_timestamp();
>
> while ((skb = tcp_write_queue_head(sk)) && skb != tcp_send_head(sk)) {
> @@ -2686,13 +2687,15 @@ static int tcp_clean_rtx_queue(struct sock *sk, s32
> *seq_rtt_p,
> if (sacked & TCPCB_SACKED_RETRANS)
> tp->retrans_out -= packets_acked;
> flag |= FLAG_RETRANS_DATA_ACKED;
> + ca_seq_rtt = -1;
> seq_rtt = -1;
> if ((flag & FLAG_DATA_ACKED) ||
> (packets_acked > 1))
> flag |= FLAG_NONHEAD_RETRANS_ACKED;
> } else {
> + ca_seq_rtt = now - scb->when;
> if (seq_rtt < 0) {
> - seq_rtt = now - scb->when;
> + seq_rtt = ca_seq_rtt;
> if (fully_acked)
> last_ackt = skb->tstamp;
> }
> @@ -2709,8 +2712,9 @@ static int tcp_clean_rtx_queue(struct sock *sk, s32
> *seq_rtt_p,
> !before(end_seq, tp->snd_up))
> tp->urg_mode = 0;
> } else {
> + ca_seq_rtt = now - scb->when;
> if (seq_rtt < 0) {
> - seq_rtt = now - scb->when;
> + seq_rtt = ca_seq_rtt;
> if (fully_acked)
> last_ackt = skb->tstamp;
> }
> @@ -2772,8 +2776,8 @@ static int tcp_clean_rtx_queue(struct sock *sk, s32
> *seq_rtt_p,
> net_invalid_timestamp()))
> rtt_us =
> ktime_us_delta(ktime_get_real(),
> last_ackt);
> - else if (seq_rtt > 0)
> - rtt_us = jiffies_to_usecs(seq_rtt);
> + else if (ca_seq_rtt > 0)
> + rtt_us = jiffies_to_usecs(ca_seq_rtt);
> }
>
> ca_ops->pkts_acked(sk, pkts_acked, rtt_us);
>
Acked-by: Ilpo Järvinen <[EMAIL PROTECTED]>
/ Reviewed-by... whatever, I don't know if they really started to use it
or not... :-)
--
i.
