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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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2
net/sched/sch_cbq.c
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@@ -513,7 +513,6 @@ static enum hrtimer_restart cbq_undelay(struct hrtimer *timer)
hrtimer_start(&q->delay_timer, time, HRTIMER_MODE_ABS_PINNED);
}
qdisc_unthrottled(sch);
__netif_schedule(qdisc_root(sch));
return HRTIMER_NORESTART;
}
@@ -819,7 +818,6 @@ cbq_dequeue(struct Qdisc *sch)
if (skb) {
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
qdisc_unthrottled(sch);
return skb;
}