[PKT_SCHED]: netetm: make qdisc friendly to outer disciplines
Netem currently dumps packets into the queue when timer expires. This patch makes work by self-clocking (more like TBF). It fixes a bug when 0 delay is requested (only doing loss or duplication). Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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8cbe1d46d6
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771018e76a
1 changed files with 67 additions and 46 deletions
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@ -138,38 +138,78 @@ static long tabledist(unsigned long mu, long sigma,
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}
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/* Put skb in the private delayed queue. */
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static int delay_skb(struct Qdisc *sch, struct sk_buff *skb)
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static int netem_delay(struct Qdisc *sch, struct sk_buff *skb)
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{
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struct netem_sched_data *q = qdisc_priv(sch);
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struct netem_skb_cb *cb = (struct netem_skb_cb *)skb->cb;
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psched_tdiff_t td;
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psched_time_t now;
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PSCHED_GET_TIME(now);
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td = tabledist(q->latency, q->jitter, &q->delay_cor, q->delay_dist);
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PSCHED_TADD2(now, td, cb->time_to_send);
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/* Always queue at tail to keep packets in order */
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if (likely(q->delayed.qlen < q->limit)) {
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struct netem_skb_cb *cb = (struct netem_skb_cb *)skb->cb;
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PSCHED_TADD2(now, td, cb->time_to_send);
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pr_debug("netem_delay: skb=%p now=%llu tosend=%llu\n", skb,
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now, cb->time_to_send);
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__skb_queue_tail(&q->delayed, skb);
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if (!timer_pending(&q->timer)) {
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q->timer.expires = jiffies + PSCHED_US2JIFFIE(td);
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add_timer(&q->timer);
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}
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return NET_XMIT_SUCCESS;
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}
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pr_debug("netem_delay: queue over limit %d\n", q->limit);
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sch->qstats.overlimits++;
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kfree_skb(skb);
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return NET_XMIT_DROP;
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}
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/*
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* Move a packet that is ready to send from the delay holding
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* list to the underlying qdisc.
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*/
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static int netem_run(struct Qdisc *sch)
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{
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struct netem_sched_data *q = qdisc_priv(sch);
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struct sk_buff *skb;
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psched_time_t now;
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PSCHED_GET_TIME(now);
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skb = skb_peek(&q->delayed);
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if (skb) {
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const struct netem_skb_cb *cb
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= (const struct netem_skb_cb *)skb->cb;
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long delay
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= PSCHED_US2JIFFIE(PSCHED_TDIFF(cb->time_to_send, now));
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pr_debug("netem_run: skb=%p delay=%ld\n", skb, delay);
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/* if more time remaining? */
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if (delay > 0) {
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mod_timer(&q->timer, jiffies + delay);
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return 1;
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}
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__skb_unlink(skb, &q->delayed);
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if (q->qdisc->enqueue(skb, q->qdisc)) {
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sch->q.qlen--;
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sch->qstats.drops++;
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}
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}
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return 0;
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}
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static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
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{
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struct netem_sched_data *q = qdisc_priv(sch);
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struct sk_buff *skb2;
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int ret;
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pr_debug("netem_enqueue skb=%p @%lu\n", skb, jiffies);
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pr_debug("netem_enqueue skb=%p\n", skb);
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/* Random packet drop 0 => none, ~0 => all */
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if (q->loss && q->loss >= get_crandom(&q->loss_cor)) {
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@ -184,7 +224,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
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&& (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
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pr_debug("netem_enqueue: dup %p\n", skb2);
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if (delay_skb(sch, skb2)) {
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if (netem_delay(sch, skb2)) {
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sch->q.qlen++;
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sch->bstats.bytes += skb2->len;
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sch->bstats.packets++;
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@ -202,7 +242,8 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
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ret = q->qdisc->enqueue(skb, q->qdisc);
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} else {
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q->counter = 0;
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ret = delay_skb(sch, skb);
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ret = netem_delay(sch, skb);
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netem_run(sch);
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}
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if (likely(ret == NET_XMIT_SUCCESS)) {
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@ -241,56 +282,35 @@ static unsigned int netem_drop(struct Qdisc* sch)
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return len;
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}
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/* Dequeue packet.
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* Move all packets that are ready to send from the delay holding
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* list to the underlying qdisc, then just call dequeue
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*/
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static struct sk_buff *netem_dequeue(struct Qdisc *sch)
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{
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struct netem_sched_data *q = qdisc_priv(sch);
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struct sk_buff *skb;
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int pending;
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pending = netem_run(sch);
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skb = q->qdisc->dequeue(q->qdisc);
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if (skb)
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if (skb) {
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pr_debug("netem_dequeue: return skb=%p\n", skb);
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sch->q.qlen--;
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sch->flags &= ~TCQ_F_THROTTLED;
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}
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else if (pending) {
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pr_debug("netem_dequeue: throttling\n");
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sch->flags |= TCQ_F_THROTTLED;
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}
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return skb;
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}
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static void netem_watchdog(unsigned long arg)
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{
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struct Qdisc *sch = (struct Qdisc *)arg;
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struct netem_sched_data *q = qdisc_priv(sch);
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struct net_device *dev = sch->dev;
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struct sk_buff *skb;
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psched_time_t now;
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pr_debug("netem_watchdog: fired @%lu\n", jiffies);
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spin_lock_bh(&dev->queue_lock);
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PSCHED_GET_TIME(now);
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while ((skb = skb_peek(&q->delayed)) != NULL) {
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const struct netem_skb_cb *cb
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= (const struct netem_skb_cb *)skb->cb;
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long delay
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= PSCHED_US2JIFFIE(PSCHED_TDIFF(cb->time_to_send, now));
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pr_debug("netem_watchdog: skb %p@%lu %ld\n",
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skb, jiffies, delay);
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/* if more time remaining? */
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if (delay > 0) {
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mod_timer(&q->timer, jiffies + delay);
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break;
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}
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__skb_unlink(skb, &q->delayed);
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if (q->qdisc->enqueue(skb, q->qdisc)) {
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sch->q.qlen--;
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sch->qstats.drops++;
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}
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}
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qdisc_run(dev);
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spin_unlock_bh(&dev->queue_lock);
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pr_debug("netem_watchdog qlen=%d\n", sch->q.qlen);
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sch->flags &= ~TCQ_F_THROTTLED;
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netif_schedule(sch->dev);
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}
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static void netem_reset(struct Qdisc *sch)
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@ -301,6 +321,7 @@ static void netem_reset(struct Qdisc *sch)
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skb_queue_purge(&q->delayed);
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sch->q.qlen = 0;
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sch->flags &= ~TCQ_F_THROTTLED;
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del_timer_sync(&q->timer);
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}
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