net_sched: accurate bytes/packets stats/rates
In commit 44b8288308ac9d (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>
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index e9eee99..160a407 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -445,7 +445,6 @@
{
__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 @@
{
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 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;
}