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net_sched: accurate bytes/packets stats/rates

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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
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;
}