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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2012-01-01 18:33:31 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-01-03 12:52:09 -0500 |
| commit | d47a0ac7b66883987275598d6039f902f4410ca9 (patch) | |
| tree | d70709d26a3833e2747126d221bbb2aa3f28ebd7 | |
| parent | 1c015b3b82c92fad375ce7dfff54799cfdfb7a15 (diff) | |
| download | talos-obmc-linux-d47a0ac7b66883987275598d6039f902f4410ca9.tar.gz talos-obmc-linux-d47a0ac7b66883987275598d6039f902f4410ca9.zip | |
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>
| -rw-r--r-- | net/sched/sch_sfq.c | 2 |
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) |
