| Message ID | 1292936699.2720.23.camel@edumazet-laptop |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
On Tue, Dec 21, 2010 at 02:04:59PM +0100, Eric Dumazet wrote: > Le mardi 21 décembre 2010 ?? 12:17 +0000, Jarek Poplawski a écrit : > > > Oops! You're right yet ;-) This skipping shouldn't happen with quantum > > bigger than max packet size, so this patch is OK. > > Thanks Jarek, here is a v2 with the scale you suggested. Very nice! Thanks as well, Jarek P. > > [PATCH v2 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> > Cc: Jarek Poplawski <jarkao2@gmail.com> > Cc: Patrick McHardy <kaber@trash.net> > --- > v2: Use a scale of 8 as Jarek suggested, instead of 18bit fields > > net/sched/sch_sfq.c | 28 +++++++++++++++++++++------- > 1 file changed, 21 insertions(+), 7 deletions(-) > > diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c > index c474b4b..f3a9fd7 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 15+1 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]; > @@ -394,7 +399,7 @@ 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); > @@ -430,8 +435,14 @@ 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--; > @@ -446,9 +457,8 @@ 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; > } > @@ -484,6 +494,7 @@ 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); > @@ -524,6 +535,7 @@ 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 { > @@ -610,7 +622,9 @@ static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl, > struct sfq_sched_data *q = qdisc_priv(sch); > const struct sfq_slot *slot = &q->slots[q->ht[cl - 1]]; > struct gnet_stats_queue qs = { .qlen = slot->qlen }; > - struct tc_sfq_xstats xstats = { .allot = slot->allot }; > + struct tc_sfq_xstats xstats = { > + .allot = slot->allot << SFQ_ALLOT_SHIFT > + }; > struct sk_buff *skb; > > slot_queue_walk(slot, skb) > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Tue, 21 Dec 2010 14:04:59 +0100 > Le mardi 21 décembre 2010 à 12:17 +0000, Jarek Poplawski a écrit : > >> Oops! You're right yet ;-) This skipping shouldn't happen with quantum >> bigger than max packet size, so this patch is OK. > > Thanks Jarek, here is a v2 with the scale you suggested. > > [PATCH v2 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> > Cc: Jarek Poplawski <jarkao2@gmail.com> > Cc: Patrick McHardy <kaber@trash.net> > --- > v2: Use a scale of 8 as Jarek suggested, instead of 18bit fields 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. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c index c474b4b..f3a9fd7 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 15+1 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]; @@ -394,7 +399,7 @@ 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); @@ -430,8 +435,14 @@ 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--; @@ -446,9 +457,8 @@ 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; } @@ -484,6 +494,7 @@ 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); @@ -524,6 +535,7 @@ 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 { @@ -610,7 +622,9 @@ static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl, struct sfq_sched_data *q = qdisc_priv(sch); const struct sfq_slot *slot = &q->slots[q->ht[cl - 1]]; struct gnet_stats_queue qs = { .qlen = slot->qlen }; - struct tc_sfq_xstats xstats = { .allot = slot->allot }; + struct tc_sfq_xstats xstats = { + .allot = slot->allot << SFQ_ALLOT_SHIFT + }; struct sk_buff *skb; slot_queue_walk(slot, skb)