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[NETEM]: avoid excessive requeues

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The netem code would call getnstimeofday() and dequeue/requeue after
every packet, even if it was waiting. Avoid this overhead by using
the throttled flag.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stephen Hemminger
2007-03-22 12:17:42 -07:00
committed by David S. Miller
parent 075aa573b7
commit 11274e5a43
2 changed files with 16 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/sched/sch_netem.c
+13 -10
View File
@@ -273,6 +273,10 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
struct netem_sched_data *q = qdisc_priv(sch);
struct sk_buff *skb;
smp_mb();
if (sch->flags & TCQ_F_THROTTLED)
return NULL;
skb = q->qdisc->dequeue(q->qdisc);
if (skb) {
const struct netem_skb_cb *cb
@@ -285,18 +289,17 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
if (PSCHED_TLESS(cb->time_to_send, now)) {
pr_debug("netem_dequeue: return skb=%p\n", skb);
sch->q.qlen--;
sch->flags &= ~TCQ_F_THROTTLED;
return skb;
} else {
qdisc_watchdog_schedule(&q->watchdog, cb->time_to_send);
if (q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS) {
qdisc_tree_decrease_qlen(q->qdisc, 1);
sch->qstats.drops++;
printk(KERN_ERR "netem: queue discpline %s could not requeue\n",
q->qdisc->ops->id);
}
}
if (unlikely(q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS)) {
qdisc_tree_decrease_qlen(q->qdisc, 1);
sch->qstats.drops++;
printk(KERN_ERR "netem: %s could not requeue\n",
q->qdisc->ops->id);
}
qdisc_watchdog_schedule(&q->watchdog, cb->time_to_send);
}
return NULL;