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authorEric Dumazet <eric.dumazet@gmail.com>2012-01-01 22:33:31 +0400
committerDavid S. Miller <davem@davemloft.net>2012-01-03 21:52:09 +0400
commitd47a0ac7b66883987275598d6039f902f4410ca9 (patch)
treed70709d26a3833e2747126d221bbb2aa3f28ebd7 /net/sched/sch_sfq.c
parent1c015b3b82c92fad375ce7dfff54799cfdfb7a15 (diff)
downloadlinux-d47a0ac7b66883987275598d6039f902f4410ca9.tar.xz
sch_sfq: dont put new flow at the end of flows
SFQ enqueue algo puts a new flow _behind_ all pre-existing flows in the circular list. In fact this is probably an old SFQ implementation bug. 100 Mbits = ~8333 full frames per second, or ~8 frames per ms. With 50 flows, it means your "new flow" will have to wait 50 packets being sent before its own packet. Thats the ~6ms. We certainly can change SFQ to give a priority advantage to new flows, so that next dequeued packet is taken from a new flow, not an old one. Reported-by: Dave Taht <dave.taht@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_sfq.c')
-rw-r--r--net/sched/sch_sfq.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index d329a8a72357..e9d5c911576d 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -366,11 +366,11 @@ sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
if (slot->qlen == 1) { /* The flow is new */
if (q->tail == NULL) { /* It is the first flow */
slot->next = x;
+ q->tail = slot;
} else {
slot->next = q->tail->next;
q->tail->next = x;
}
- q->tail = slot;
slot->allot = q->scaled_quantum;
}
if (++sch->q.qlen <= q->limit)