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net_sched: remove generic throttled management

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__QDISC_STATE_THROTTLED bit manipulation is rather expensive
for HTB and few others.

I already removed it for sch_fq in commit f2600cf02b
("net: sched: avoid costly atomic operation in fq_dequeue()")
and so far nobody complained.

When one ore more packets are stuck in one or more throttled
HTB class, a htb dequeue() performs two atomic operations
to clear/set __QDISC_STATE_THROTTLED bit, while root qdisc
lock is held.

Removing this pair of atomic operations bring me a 8 % performance
increase on 200 TCP_RR tests, in presence of throttled classes.

This patch has no side effect, since nothing actually uses
disc_is_throttled() anymore.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2016-06-10 16:41:39 -07:00
committed by David S. Miller
parent 42117927ca
commit 45f50bed1d
9 changed files with 6 additions and 35 deletions
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3
net/sched/sch_htb.c
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@@ -889,7 +889,6 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
if (skb != NULL) {
ok:
qdisc_bstats_update(sch, skb);
qdisc_unthrottled(sch);
qdisc_qstats_backlog_dec(sch, skb);
sch->q.qlen--;
return skb;
@@ -929,7 +928,7 @@ ok:
}
qdisc_qstats_overlimit(sch);
if (likely(next_event > q->now))
qdisc_watchdog_schedule_ns(&q->watchdog, next_event, true);
qdisc_watchdog_schedule_ns(&q->watchdog, next_event);
else
schedule_work(&q->work);
fin: