From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: jarkao2@gmail.com, kaber@trash.net, netdev@vger.kernel.org
Subject: [PATCH v3 net-next-2.6] sch_sfq: allow big packets and be fair
Date: Wed, 29 Dec 2010 08:53:33 +0100 [thread overview]
Message-ID: <1293609213.2691.3.camel@edumazet-laptop> (raw)
In-Reply-To: <20101228.134655.112609314.davem@davemloft.net>
Le mardi 28 décembre 2010 à 13:46 -0800, David Miller a écrit :
> Eric this doesn't apply cleanly, since the code in sfq_dump_class_stats()
> is a bit different in net-next-2.6
>
> Please respin this and resubmit.
Sure, here is the version for latest net-next
Thanks
[PATCH v3 net-next-2.6] sch_sfq: allow big packets and be fair
SFQ is currently 'limited' to small packets, because it uses a 15bit
allotment number per flow. Introduce a scale by 8, so that we can handle
full size TSO/GRO packets.
Use appropriate handling to make sure allot is positive before a new
packet is dequeued, so that fairness is respected.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Jarek Poplawski <jarkao2@gmail.com>
Cc: Patrick McHardy <kaber@trash.net>
---
v3: respin after commit ee09b3c1cf (fix sfq class stats handling)
v2: Use a scale of 8 as Jarek suggested, instead of 18bit fields
net/sched/sch_sfq.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index 0ce421d..79c8967 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -67,7 +67,7 @@
IMPLEMENTATION:
This implementation limits maximal queue length to 128;
- maximal mtu to 2^15-1; max 128 flows, number of hash buckets to 1024.
+ max mtu to 2^18-1; max 128 flows, number of hash buckets to 1024.
The only goal of this restrictions was that all data
fit into one 4K page on 32bit arches.
@@ -77,6 +77,11 @@
#define SFQ_SLOTS 128 /* max number of flows */
#define SFQ_EMPTY_SLOT 255
#define SFQ_HASH_DIVISOR 1024
+/* We use 16 bits to store allot, and want to handle packets up to 64K
+ * Scale allot by 8 (1<<3) so that no overflow occurs.
+ */
+#define SFQ_ALLOT_SHIFT 3
+#define SFQ_ALLOT_SIZE(X) DIV_ROUND_UP(X, 1 << SFQ_ALLOT_SHIFT)
/* This type should contain at least SFQ_DEPTH + SFQ_SLOTS values */
typedef unsigned char sfq_index;
@@ -115,7 +120,7 @@ struct sfq_sched_data
struct timer_list perturb_timer;
u32 perturbation;
sfq_index cur_depth; /* depth of longest slot */
-
+ unsigned short scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */
struct sfq_slot *tail; /* current slot in round */
sfq_index ht[SFQ_HASH_DIVISOR]; /* Hash table */
struct sfq_slot slots[SFQ_SLOTS];
@@ -395,7 +400,7 @@ sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
q->tail->next = x;
}
q->tail = slot;
- slot->allot = q->quantum;
+ slot->allot = q->scaled_quantum;
}
if (++sch->q.qlen <= q->limit) {
sch->bstats.bytes += qdisc_pkt_len(skb);
@@ -431,8 +436,14 @@ sfq_dequeue(struct Qdisc *sch)
if (q->tail == NULL)
return NULL;
+next_slot:
a = q->tail->next;
slot = &q->slots[a];
+ if (slot->allot <= 0) {
+ q->tail = slot;
+ slot->allot += q->scaled_quantum;
+ goto next_slot;
+ }
skb = slot_dequeue_head(slot);
sfq_dec(q, a);
sch->q.qlen--;
@@ -447,9 +458,8 @@ sfq_dequeue(struct Qdisc *sch)
return skb;
}
q->tail->next = next_a;
- } else if ((slot->allot -= qdisc_pkt_len(skb)) <= 0) {
- q->tail = slot;
- slot->allot += q->quantum;
+ } else {
+ slot->allot -= SFQ_ALLOT_SIZE(qdisc_pkt_len(skb));
}
return skb;
}
@@ -485,6 +495,7 @@ static int sfq_change(struct Qdisc *sch, struct nlattr *opt)
sch_tree_lock(sch);
q->quantum = ctl->quantum ? : psched_mtu(qdisc_dev(sch));
+ q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
q->perturb_period = ctl->perturb_period * HZ;
if (ctl->limit)
q->limit = min_t(u32, ctl->limit, SFQ_DEPTH - 1);
@@ -525,6 +536,7 @@ static int sfq_init(struct Qdisc *sch, struct nlattr *opt)
q->tail = NULL;
if (opt == NULL) {
q->quantum = psched_mtu(qdisc_dev(sch));
+ q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
q->perturb_period = 0;
q->perturbation = net_random();
} else {
@@ -617,7 +629,7 @@ static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
if (idx != SFQ_EMPTY_SLOT) {
const struct sfq_slot *slot = &q->slots[idx];
- xstats.allot = slot->allot;
+ xstats.allot = slot->allot << SFQ_ALLOT_SHIFT;
qs.qlen = slot->qlen;
slot_queue_walk(slot, skb)
qs.backlog += qdisc_pkt_len(skb);
next prev parent reply other threads:[~2010-12-29 7:53 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-15 14:03 [PATCH] net_sched: sch_sfq: fix allot handling Eric Dumazet
2010-12-15 16:03 ` Patrick McHardy
2010-12-15 16:27 ` Eric Dumazet
2010-12-15 16:40 ` [PATCH v2] " Eric Dumazet
2010-12-15 16:43 ` Patrick McHardy
2010-12-15 16:55 ` Eric Dumazet
2010-12-15 17:03 ` Patrick McHardy
2010-12-15 17:09 ` Eric Dumazet
2010-12-15 17:21 ` Patrick McHardy
2010-12-15 17:30 ` [PATCH v3] " Eric Dumazet
2010-12-15 18:18 ` [PATCH net-next-2.6] net_sched: sch_sfq: add backlog info in sfq_dump_class_stats() Eric Dumazet
2010-12-15 19:10 ` Eric Dumazet
2010-12-16 8:16 ` Jarek Poplawski
2010-12-16 10:18 ` [PATCH v2 " Eric Dumazet
2010-12-16 11:03 ` [PATCH " Eric Dumazet
2010-12-16 13:09 ` Jarek Poplawski
2010-12-20 21:14 ` David Miller
2010-12-20 21:18 ` [PATCH v3] net_sched: sch_sfq: fix allot handling David Miller
2010-12-16 13:08 ` [PATCH v2] " Eric Dumazet
2010-12-17 16:52 ` [RFC PATCH] net_sched: sch_sfq: better struct layouts Eric Dumazet
2010-12-19 21:22 ` Jarek Poplawski
2010-12-20 17:02 ` [PATCH v2] " Eric Dumazet
2010-12-20 21:33 ` David Miller
2010-12-20 21:42 ` Eric Dumazet
2010-12-20 22:54 ` [PATCH v3 net-next-2.6] " Eric Dumazet
2010-12-21 5:33 ` David Miller
2010-12-20 22:55 ` [PATCH v2] " Jarek Poplawski
2010-12-20 23:16 ` [PATCH net-next-2.6] sch_sfq: allow big packets and be fair Eric Dumazet
2010-12-21 10:15 ` Jarek Poplawski
2010-12-21 10:30 ` Jarek Poplawski
2010-12-21 10:44 ` Eric Dumazet
2010-12-21 10:56 ` Jarek Poplawski
2010-12-21 10:57 ` Eric Dumazet
2010-12-21 11:39 ` Jarek Poplawski
2010-12-21 12:17 ` Jarek Poplawski
2010-12-21 13:04 ` [PATCH v2 " Eric Dumazet
2010-12-21 13:47 ` Jarek Poplawski
2010-12-28 21:46 ` David Miller
2010-12-29 7:53 ` Eric Dumazet [this message]
2010-12-31 20:48 ` [PATCH v3 " David Miller
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