On Fri, 20 Oct 2006 23:42:28 -0700 (PDT) David Miller <davem@xxxxxxxxxxxxx> wrote: > From: John Heffner <jheffner@xxxxxxx> > Date: Fri, 20 Oct 2006 23:11:15 -0400 > > > I think that what's going on is that since you're using netem, tcp is > > double-counting the cloned skb's sitting in the txqueue. Since pretty > > much the full BDP is sitting in your txqueue, you're needing about > > 2xBDP. I think this double-counting isn't strictly necessary. Can > > anyone think of a good reason why this is done (skb_set_owner_w() in > > tcp_transmit_skb())? It's late and my brain may not be working right.. ;) > > Indeed, netem should orphan the SKB as soon as it queues. > Try this: > > diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c > index 45939ba..ef8874b 100644 > --- a/net/sched/sch_netem.c > +++ b/net/sched/sch_netem.c > @@ -170,6 +170,8 @@ static int netem_enqueue(struct sk_buff > return NET_XMIT_BYPASS; > } > > + skb_orphan(skb); > + > /* > * If we need to duplicate packet, then re-insert at top of the > * qdisc tree, since parent queuer expects that only one > - > To unsubscribe from this list: send the line "unsubscribe linux-net" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html Yeah, that's good. I run netem on an intermediate machine (bridge or router) when running tests to avoid this and other local feedback scenario's. - To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
