Commit 075aa573 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
Browse files

[NETEM]: Optimize tfifo 



In most cases, the next packet will be sent after the
last one. So optimize that case.

Signed-off-by: default avatarStephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b407621c

net/sched/sch_netem.c

+11 −4
Original line number Diff line number Diff line
@@ -479,22 +479,28 @@ static int netem_change(struct Qdisc *sch, struct rtattr *opt) 
 */

struct fifo_sched_data {

	u32 limit;

	psched_time_t oldest;

};



static int tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)

{

	struct fifo_sched_data *q = qdisc_priv(sch);

	struct sk_buff_head *list = &sch->q;

	const struct netem_skb_cb *ncb

		= (const struct netem_skb_cb *)nskb->cb;

	psched_time_t tnext = ((struct netem_skb_cb *)nskb->cb)->time_to_send;

	struct sk_buff *skb;



	if (likely(skb_queue_len(list) < q->limit)) {

		/* Optimize for add at tail */

		if (likely(skb_queue_empty(list) || !PSCHED_TLESS(tnext, q->oldest))) {

			q->oldest = tnext;

			return qdisc_enqueue_tail(nskb, sch);

		}



		skb_queue_reverse_walk(list, skb) {

			const struct netem_skb_cb *cb

				= (const struct netem_skb_cb *)skb->cb;



			if (!PSCHED_TLESS(ncb->time_to_send, cb->time_to_send))

			if (!PSCHED_TLESS(tnext, cb->time_to_send))

				break;

		}
@@ -507,7 +513,7 @@ static int tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch) 
		return NET_XMIT_SUCCESS;

	}



	return qdisc_drop(nskb, sch);

	return qdisc_reshape_fail(nskb, sch);

}



static int tfifo_init(struct Qdisc *sch, struct rtattr *opt)
@@ -523,6 +529,7 @@ static int tfifo_init(struct Qdisc *sch, struct rtattr *opt) 
	} else

		q->limit = max_t(u32, sch->dev->tx_queue_len, 1);



	PSCHED_SET_PASTPERFECT(q->oldest);

	return 0;

}