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Commit 087c1a60 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

net: sched: run ingress qdisc without locks 

TC classifiers/actions were converted to RCU by John in the series:
http://thread.gmane.org/gmane.linux.network/329739/focus=329739


and many follow on patches.
This is the last patch from that series that finally drops
ingress spin_lock.

Single cpu ingress+u32 performance goes from 22.9 Mpps to 24.5 Mpps.

In two cpu case when both cores are receiving traffic on the same
device and go into the same ingress+u32 the performance jumps
from 4.5 + 4.5 Mpps to 23.5 + 23.5 Mpps

Signed-off-by: default avatarJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a89f96c9

net/core/dev.c

+0 −2
Original line number Diff line number Diff line
@@ -3547,10 +3547,8 @@ static int ing_filter(struct sk_buff *skb, struct netdev_queue *rxq) 


	q = rcu_dereference(rxq->qdisc);

	if (q != &noop_qdisc) {

		spin_lock(qdisc_lock(q));

		if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))

			result = qdisc_enqueue_root(skb, q);

		spin_unlock(qdisc_lock(q));

	}



	return result;

net/sched/sch_ingress.c

+3 −2
Original line number Diff line number Diff line
@@ -65,11 +65,11 @@ static int ingress_enqueue(struct sk_buff *skb, struct Qdisc *sch) 


	result = tc_classify(skb, fl, &res);



	qdisc_bstats_update(sch, skb);

	qdisc_bstats_update_cpu(sch, skb);

	switch (result) {

	case TC_ACT_SHOT:

		result = TC_ACT_SHOT;

		qdisc_qstats_drop(sch);

		qdisc_qstats_drop_cpu(sch);

		break;

	case TC_ACT_STOLEN:

	case TC_ACT_QUEUED:
@@ -91,6 +91,7 @@ static int ingress_enqueue(struct sk_buff *skb, struct Qdisc *sch) 
static int ingress_init(struct Qdisc *sch, struct nlattr *opt)

{

	net_inc_ingress_queue();

	sch->flags |= TCQ_F_CPUSTATS;



	return 0;

}