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authorStephen Hemminger <shemminger@linux-foundation.org>2007-03-22 12:17:42 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-04-25 22:27:22 -0700
commit11274e5a43266d531140530adebead6903380caf (patch)
tree38c365a3835c9e5973fb1941a31dde8cc4856724 /net/sched/sch_netem.c
parent075aa573b74a732aeff487ab77d3fbd627c10856 (diff)
[NETEM]: avoid excessive requeues
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>
Diffstat (limited to 'net/sched/sch_netem.c')
-rw-r--r--net/sched/sch_netem.c23
1 files changed, 13 insertions, 10 deletions
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 7e9e658d4d93..fb49e9e7ace0 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -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;