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net_sched: accurate bytes/packets stats/rates 

In commit 44b8288308 (net_sched: pfifo_head_drop problem), we fixed
a problem with pfifo_head drops that incorrectly decreased
sch->bstats.bytes and sch->bstats.packets

Several qdiscs (CHOKe, SFQ, pfifo_head, ...) are able to drop a
previously enqueued packet, and bstats cannot be changed, so
bstats/rates are not accurate (over estimated)

This patch changes the qdisc_bstats updates to be done at dequeue() time
instead of enqueue() time. bstats counters no longer account for dropped
frames, and rates are more correct, since enqueue() bursts dont have
effect on dequeue() rate.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2011-01-20 23:31:33 -08:00 committed by David S. Miller
parent b30532515f
commit 9190b3b320
14 changed files with 29 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/net/sch_generic.h
View File

@ -445,7 +445,6 @@ static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
{
__skb_queue_tail(list, skb);
sch->qstats.backlog += qdisc_pkt_len(skb);
qdisc_bstats_update(sch, skb);
return NET_XMIT_SUCCESS;
}
@ -460,8 +459,10 @@ static inline struct sk_buff *__qdisc_dequeue_head(struct Qdisc *sch,
{
struct sk_buff *skb = __skb_dequeue(list);
if (likely(skb != NULL))
if (likely(skb != NULL)) {
sch->qstats.backlog -= qdisc_pkt_len(skb);
qdisc_bstats_update(sch, skb);
}
return skb;
}
@ -474,10 +475,11 @@ static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
struct sk_buff_head *list)
{
struct sk_buff *skb = __qdisc_dequeue_head(sch, list);
struct sk_buff *skb = __skb_dequeue(list);
if (likely(skb != NULL)) {
unsigned int len = qdisc_pkt_len(skb);
sch->qstats.backlog -= len;
kfree_skb(skb);
return len;
}

3
net/sched/sch_cbq.c
View File

@ -390,7 +390,6 @@ cbq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
ret = qdisc_enqueue(skb, cl->q);
if (ret == NET_XMIT_SUCCESS) {
sch->q.qlen++;
qdisc_bstats_update(sch, skb);
cbq_mark_toplevel(q, cl);
if (!cl->next_alive)
cbq_activate_class(cl);
@ -649,7 +648,6 @@ static int cbq_reshape_fail(struct sk_buff *skb, struct Qdisc *child)
ret = qdisc_enqueue(skb, cl->q);
if (ret == NET_XMIT_SUCCESS) {
sch->q.qlen++;
qdisc_bstats_update(sch, skb);
if (!cl->next_alive)
cbq_activate_class(cl);
return 0;
@ -971,6 +969,7 @@ cbq_dequeue(struct Qdisc *sch)
skb = cbq_dequeue_1(sch);
if (skb) {
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
sch->flags &= ~TCQ_F_THROTTLED;
return skb;

2
net/sched/sch_drr.c
View File

@ -376,7 +376,6 @@ static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch)
}
bstats_update(&cl->bstats, skb);
qdisc_bstats_update(sch, skb);
sch->q.qlen++;
return err;
@ -403,6 +402,7 @@ static struct sk_buff *drr_dequeue(struct Qdisc *sch)
skb = qdisc_dequeue_peeked(cl->qdisc);
if (cl->qdisc->q.qlen == 0)
list_del(&cl->alist);
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
return skb;
}

2
net/sched/sch_dsmark.c
View File

@ -260,7 +260,6 @@ static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)
return err;
}
qdisc_bstats_update(sch, skb);
sch->q.qlen++;
return NET_XMIT_SUCCESS;
@ -283,6 +282,7 @@ static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
if (skb == NULL)
return NULL;
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
index = skb->tc_index & (p->indices - 1);

5
net/sched/sch_fifo.c
View File

@ -46,17 +46,14 @@ static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc* sch)
{
struct sk_buff *skb_head;
struct fifo_sched_data *q = qdisc_priv(sch);
if (likely(skb_queue_len(&sch->q) < q->limit))
return qdisc_enqueue_tail(skb, sch);
/* queue full, remove one skb to fulfill the limit */
skb_head = qdisc_dequeue_head(sch);
__qdisc_queue_drop_head(sch, &sch->q);
sch->qstats.drops++;
kfree_skb(skb_head);
qdisc_enqueue_tail(skb, sch);
return NET_XMIT_CN;

2
net/sched/sch_hfsc.c
View File

@ -1600,7 +1600,6 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
set_active(cl, qdisc_pkt_len(skb));
bstats_update(&cl->bstats, skb);
qdisc_bstats_update(sch, skb);
sch->q.qlen++;
return NET_XMIT_SUCCESS;
@ -1666,6 +1665,7 @@ hfsc_dequeue(struct Qdisc *sch)
}
sch->flags &= ~TCQ_F_THROTTLED;
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
return skb;

12
net/sched/sch_htb.c
View File

@ -574,7 +574,6 @@ static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
}
sch->q.qlen++;
qdisc_bstats_update(sch, skb);
return NET_XMIT_SUCCESS;
}
@ -842,7 +841,7 @@ next:
static struct sk_buff *htb_dequeue(struct Qdisc *sch)
{
struct sk_buff *skb = NULL;
struct sk_buff *skb;
struct htb_sched *q = qdisc_priv(sch);
int level;
psched_time_t next_event;
@ -851,6 +850,8 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
/* try to dequeue direct packets as high prio (!) to minimize cpu work */
skb = __skb_dequeue(&q->direct_queue);
if (skb != NULL) {
ok:
qdisc_bstats_update(sch, skb);
sch->flags &= ~TCQ_F_THROTTLED;
sch->q.qlen--;
return skb;
@ -884,11 +885,8 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
int prio = ffz(m);
m |= 1 << prio;
skb = htb_dequeue_tree(q, prio, level);
if (likely(skb != NULL)) {
sch->q.qlen--;
sch->flags &= ~TCQ_F_THROTTLED;
goto fin;
}
if (likely(skb != NULL))
goto ok;
}
}
sch->qstats.overlimits++;

2
net/sched/sch_multiq.c
View File

@ -83,7 +83,6 @@ multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
ret = qdisc_enqueue(skb, qdisc);
if (ret == NET_XMIT_SUCCESS) {
qdisc_bstats_update(sch, skb);
sch->q.qlen++;
return NET_XMIT_SUCCESS;
}
@ -112,6 +111,7 @@ static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
qdisc = q->queues[q->curband];
skb = qdisc->dequeue(qdisc);
if (skb) {
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
return skb;
}

3
net/sched/sch_netem.c
View File

@ -240,7 +240,6 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
if (likely(ret == NET_XMIT_SUCCESS)) {
sch->q.qlen++;
qdisc_bstats_update(sch, skb);
} else if (net_xmit_drop_count(ret)) {
sch->qstats.drops++;
}
@ -289,6 +288,7 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
skb->tstamp.tv64 = 0;
#endif
pr_debug("netem_dequeue: return skb=%p\n", skb);
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
return skb;
}
@ -476,7 +476,6 @@ static int tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
__skb_queue_after(list, skb, nskb);
sch->qstats.backlog += qdisc_pkt_len(nskb);
qdisc_bstats_update(sch, nskb);
return NET_XMIT_SUCCESS;
}

2
net/sched/sch_prio.c
View File

@ -84,7 +84,6 @@ prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
ret = qdisc_enqueue(skb, qdisc);
if (ret == NET_XMIT_SUCCESS) {
qdisc_bstats_update(sch, skb);
sch->q.qlen++;
return NET_XMIT_SUCCESS;
}
@ -116,6 +115,7 @@ static struct sk_buff *prio_dequeue(struct Qdisc* sch)
struct Qdisc *qdisc = q->queues[prio];
struct sk_buff *skb = qdisc->dequeue(qdisc);
if (skb) {
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
return skb;
}

11
net/sched/sch_red.c
View File

@ -94,7 +94,6 @@ static int red_enqueue(struct sk_buff *skb, struct Qdisc* sch)
ret = qdisc_enqueue(skb, child);
if (likely(ret == NET_XMIT_SUCCESS)) {
qdisc_bstats_update(sch, skb);
sch->q.qlen++;
} else if (net_xmit_drop_count(ret)) {
q->stats.pdrop++;
@ -114,11 +113,13 @@ static struct sk_buff * red_dequeue(struct Qdisc* sch)
struct Qdisc *child = q->qdisc;
skb = child->dequeue(child);
if (skb)
if (skb) {
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
else if (!red_is_idling(&q->parms))
red_start_of_idle_period(&q->parms);
} else {
if (!red_is_idling(&q->parms))
red_start_of_idle_period(&q->parms);
}
return skb;
}

5
net/sched/sch_sfq.c
View File

@ -402,10 +402,8 @@ sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
q->tail = slot;
slot->allot = q->scaled_quantum;
}
if (++sch->q.qlen <= q->limit) {
qdisc_bstats_update(sch, skb);
if (++sch->q.qlen <= q->limit)
return NET_XMIT_SUCCESS;
}
sfq_drop(sch);
return NET_XMIT_CN;
@ -445,6 +443,7 @@ next_slot:
}
skb = slot_dequeue_head(slot);
sfq_dec(q, a);
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
sch->qstats.backlog -= qdisc_pkt_len(skb);

2
net/sched/sch_tbf.c
View File

@ -134,7 +134,6 @@ static int tbf_enqueue(struct sk_buff *skb, struct Qdisc* sch)
}
sch->q.qlen++;
qdisc_bstats_update(sch, skb);
return NET_XMIT_SUCCESS;
}
@ -187,6 +186,7 @@ static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
q->ptokens = ptoks;
sch->q.qlen--;
sch->flags &= ~TCQ_F_THROTTLED;
qdisc_bstats_update(sch, skb);
return skb;
}

3
net/sched/sch_teql.c
View File

@ -87,7 +87,6 @@ teql_enqueue(struct sk_buff *skb, struct Qdisc* sch)
if (q->q.qlen < dev->tx_queue_len) {
__skb_queue_tail(&q->q, skb);
qdisc_bstats_update(sch, skb);
return NET_XMIT_SUCCESS;
}
@ -111,6 +110,8 @@ teql_dequeue(struct Qdisc* sch)
dat->m->slaves = sch;
netif_wake_queue(m);
}
} else {
qdisc_bstats_update(sch, skb);
}
sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
return skb;