On Sun, 2012-06-17 at 15:30 -0700, Dave Täht wrote:
> Lossless IP networks are not possible. Dropping packets is the
> fastest way to get back to a target delay, and if that involves
> dropping ECN marked packets, so be it. When a network is in a
> more steady state, ECN is fine...
>
Just disable ecn then ? By the way ECN is disabled by default on CoDel.
> My choice of "2 * target" as a threshold for dropping ECN
> marked packets is entirely arbitrary.
> ---
> include/net/codel.h | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/codel.h b/include/net/codel.h
> index 550debf..26944a0 100644
> --- a/include/net/codel.h
> +++ b/include/net/codel.h
> @@ -280,7 +280,8 @@ static struct sk_buff *codel_dequeue(struct Qdisc *sch,
> * since there is no more divide
> */
> codel_Newton_step(vars);
> - if (params->ecn && INET_ECN_set_ce(skb)) {
> + if (params->ecn && INET_ECN_set_ce(skb) &&
> + vars->ldelay <= 2 * params->target) {
> stats->ecn_mark++;
> vars->drop_next =
>
> codel_control_law(vars->drop_next,
> @@ -305,7 +306,8 @@ static struct sk_buff *codel_dequeue(struct Qdisc *sch,
> }
> }
> } else if (drop) {
> - if (params->ecn && INET_ECN_set_ce(skb)) {
> + if (params->ecn && INET_ECN_set_ce(skb) &&
> + vars->ldelay <= 2 * params->target) {
> stats->ecn_mark++;
> } else {
> qdisc_drop(skb, sch);
Hmm, while I understand the idea, patch is wrong.
if (A && B && C)
Even if (C) is false, but A is true, B is evaluated.
Also, a 2 * target value is arbitrary, why not instead provide a real
attribute, that user can set with tc command ?
_______________________________________________
Codel mailing list
[email protected]
https://lists.bufferbloat.net/listinfo/codel
