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authorEric Dumazet <eric.dumazet@gmail.com>2010-12-20 13:18:16 -0800
committerDavid S. Miller <davem@davemloft.net>2010-12-20 13:18:16 -0800
commitaa3e219997e4b949be4199660936099ded0b401f (patch)
treee463d695dbf0e92f7fd2c6b3132bbb9c38493829 /net
parent914e5cea14b2e4651cdb0707e0936b43246deda0 (diff)
net_sched: sch_sfq: fix allot handling
When deploying SFQ/IFB here at work, I found the allot management was pretty wrong in sfq, even changing allot from short to int... We should init allot for each new flow, not using a previous value found in slot. Before patch, I saw bursts of several packets per flow, apparently denying the default "quantum 1514" limit I had on my SFQ class. class sfq 11:1 parent 11: (dropped 0, overlimits 0 requeues 0) backlog 0b 7p requeues 0 allot 11546 class sfq 11:46 parent 11: (dropped 0, overlimits 0 requeues 0) backlog 0b 1p requeues 0 allot -23873 class sfq 11:78 parent 11: (dropped 0, overlimits 0 requeues 0) backlog 0b 5p requeues 0 allot 11393 After patch, better fairness among each flow, allot limit being respected, allot is positive : class sfq 11:e parent 11: (dropped 0, overlimits 0 requeues 86) backlog 0b 3p requeues 86 allot 596 class sfq 11:94 parent 11: (dropped 0, overlimits 0 requeues 0) backlog 0b 3p requeues 0 allot 1468 class sfq 11:a4 parent 11: (dropped 0, overlimits 0 requeues 0) backlog 0b 4p requeues 0 allot 650 class sfq 11:bb parent 11: (dropped 0, overlimits 0 requeues 0) backlog 0b 3p requeues 0 allot 596 Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sched/sch_sfq.c20
1 files changed, 8 insertions, 12 deletions
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index 3cf478d012d..7150705f1d0 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -270,7 +270,6 @@ static unsigned int sfq_drop(struct Qdisc *sch)
/* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */
d = q->next[q->tail];
q->next[q->tail] = q->next[d];
- q->allot[q->next[d]] += q->quantum;
skb = q->qs[d].prev;
len = qdisc_pkt_len(skb);
__skb_unlink(skb, &q->qs[d]);
@@ -321,14 +320,13 @@ sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
sfq_inc(q, x);
if (q->qs[x].qlen == 1) { /* The flow is new */
if (q->tail == SFQ_DEPTH) { /* It is the first flow */
- q->tail = x;
q->next[x] = x;
- q->allot[x] = q->quantum;
} else {
q->next[x] = q->next[q->tail];
q->next[q->tail] = x;
- q->tail = x;
}
+ q->tail = x;
+ q->allot[x] = q->quantum;
}
if (++sch->q.qlen <= q->limit) {
sch->bstats.bytes += qdisc_pkt_len(skb);
@@ -359,13 +357,13 @@ sfq_dequeue(struct Qdisc *sch)
{
struct sfq_sched_data *q = qdisc_priv(sch);
struct sk_buff *skb;
- sfq_index a, old_a;
+ sfq_index a, next_a;
/* No active slots */
if (q->tail == SFQ_DEPTH)
return NULL;
- a = old_a = q->next[q->tail];
+ a = q->next[q->tail];
/* Grab packet */
skb = __skb_dequeue(&q->qs[a]);
@@ -376,17 +374,15 @@ sfq_dequeue(struct Qdisc *sch)
/* Is the slot empty? */
if (q->qs[a].qlen == 0) {
q->ht[q->hash[a]] = SFQ_DEPTH;
- a = q->next[a];
- if (a == old_a) {
+ next_a = q->next[a];
+ if (a == next_a) {
q->tail = SFQ_DEPTH;
return skb;
}
- q->next[q->tail] = a;
- q->allot[a] += q->quantum;
+ q->next[q->tail] = next_a;
} else if ((q->allot[a] -= qdisc_pkt_len(skb)) <= 0) {
- q->tail = a;
- a = q->next[a];
q->allot[a] += q->quantum;
+ q->tail = a;
}
return skb;
}