From: Dave Taht <[email protected]>
ECN can be gamed, and it is generally faster under overload
to drop rather than mark packets, to get back to a target.
This patch adds support for ecn_target which controls when
codel and fq_codel will start dropping rather than marking
ecn tagged packets.
The default is 15ms.
---
include/linux/pkt_sched.h | 2 ++
include/net/codel.h | 11 +++++++++--
net/sched/sch_codel.c | 13 ++++++++++++-
net/sched/sch_fq_codel.c | 12 +++++++++++-
4 files changed, 34 insertions(+), 4 deletions(-)
diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h
index 32aef0a..f0dcf8c 100644
--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -663,6 +663,7 @@ enum {
TCA_CODEL_LIMIT,
TCA_CODEL_INTERVAL,
TCA_CODEL_ECN,
+ TCA_CODEL_ECN_TARGET,
__TCA_CODEL_MAX
};
@@ -691,6 +692,7 @@ enum {
TCA_FQ_CODEL_ECN,
TCA_FQ_CODEL_FLOWS,
TCA_FQ_CODEL_QUANTUM,
+ TCA_FQ_CODEL_ECN_TARGET,
__TCA_FQ_CODEL_MAX
};
diff --git a/include/net/codel.h b/include/net/codel.h
index 550debf..8a6a2b0 100644
--- a/include/net/codel.h
+++ b/include/net/codel.h
@@ -111,11 +111,13 @@ static inline u32 codel_time_to_us(codel_time_t val)
* @target: target queue size (in time units)
* @interval: width of moving time window
* @ecn: is Explicit Congestion Notification enabled
+ * @ecn_target: ecn target for queue drop anyway (in time units)
*/
struct codel_params {
codel_time_t target;
codel_time_t interval;
bool ecn;
+ codel_time_t ecn_target;
};
/**
@@ -161,6 +163,7 @@ static void codel_params_init(struct codel_params *params)
params->interval = MS2TIME(100);
params->target = MS2TIME(5);
params->ecn = false;
+ params->ecn_target = MS2TIME(15);
}
static void codel_vars_init(struct codel_vars *vars)
@@ -280,7 +283,9 @@ static struct sk_buff *codel_dequeue(struct Qdisc *sch,
* since there is no more divide
*/
codel_Newton_step(vars);
- if (params->ecn && INET_ECN_set_ce(skb)) {
+ if (params->ecn &&
+ params->ecn_target > vars->ldelay &&
+ INET_ECN_set_ce(skb)) {
stats->ecn_mark++;
vars->drop_next =
codel_control_law(vars->drop_next,
@@ -305,7 +310,9 @@ static struct sk_buff *codel_dequeue(struct Qdisc *sch,
}
}
} else if (drop) {
- if (params->ecn && INET_ECN_set_ce(skb)) {
+ if (params->ecn &&
+ params->ecn_target > vars->ldelay &&
+ INET_ECN_set_ce(skb)) {
stats->ecn_mark++;
} else {
qdisc_drop(skb, sch);
diff --git a/net/sched/sch_codel.c b/net/sched/sch_codel.c
index 2f9ab17..b008a35 100644
--- a/net/sched/sch_codel.c
+++ b/net/sched/sch_codel.c
@@ -109,6 +109,7 @@ static const struct nla_policy codel_policy[TCA_CODEL_MAX +
1] = {
[TCA_CODEL_LIMIT] = { .type = NLA_U32 },
[TCA_CODEL_INTERVAL] = { .type = NLA_U32 },
[TCA_CODEL_ECN] = { .type = NLA_U32 },
+ [TCA_CODEL_ECN_TARGET] = { .type = NLA_U32 },
};
static int codel_change(struct Qdisc *sch, struct nlattr *opt)
@@ -133,6 +134,13 @@ static int codel_change(struct Qdisc *sch, struct nlattr
*opt)
q->params.target = ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT;
}
+ if (tb[TCA_CODEL_ECN_TARGET]) {
+ u32 target = nla_get_u32(tb[TCA_CODEL_TARGET]);
+
+ q->params.ecn_target = ((u64)target * NSEC_PER_USEC) >>
+ CODEL_SHIFT;
+ }
+
if (tb[TCA_CODEL_INTERVAL]) {
u32 interval = nla_get_u32(tb[TCA_CODEL_INTERVAL]);
@@ -145,6 +153,7 @@ static int codel_change(struct Qdisc *sch, struct nlattr
*opt)
if (tb[TCA_CODEL_ECN])
q->params.ecn = !!nla_get_u32(tb[TCA_CODEL_ECN]);
+
qlen = sch->q.qlen;
while (sch->q.qlen > sch->limit) {
struct sk_buff *skb = __skb_dequeue(&sch->q);
@@ -199,7 +208,9 @@ static int codel_dump(struct Qdisc *sch, struct sk_buff
*skb)
nla_put_u32(skb, TCA_CODEL_INTERVAL,
codel_time_to_us(q->params.interval)) ||
nla_put_u32(skb, TCA_CODEL_ECN,
- q->params.ecn))
+ q->params.ecn) ||
+ nla_put_u32(skb, TCA_CODEL_ECN_TARGET,
+ codel_time_to_us(q->params.ecn_target)))
goto nla_put_failure;
return nla_nest_end(skb, opts);
diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c
index 9fc1c62..d974e07 100644
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -297,6 +297,7 @@ static const struct nla_policy
fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = {
[TCA_FQ_CODEL_ECN] = { .type = NLA_U32 },
[TCA_FQ_CODEL_FLOWS] = { .type = NLA_U32 },
[TCA_FQ_CODEL_QUANTUM] = { .type = NLA_U32 },
+ [TCA_FQ_CODEL_ECN_TARGET] = { .type = NLA_U32 },
};
static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt)
@@ -327,6 +328,13 @@ static int fq_codel_change(struct Qdisc *sch, struct
nlattr *opt)
q->cparams.target = (target * NSEC_PER_USEC) >> CODEL_SHIFT;
}
+ if (tb[TCA_FQ_CODEL_ECN_TARGET]) {
+ u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]);
+
+ q->cparams.ecn_target = (target * NSEC_PER_USEC) >>
+ CODEL_SHIFT;
+ }
+
if (tb[TCA_FQ_CODEL_INTERVAL]) {
u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]);
@@ -447,7 +455,9 @@ static int fq_codel_dump(struct Qdisc *sch, struct sk_buff
*skb)
nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM,
q->quantum) ||
nla_put_u32(skb, TCA_FQ_CODEL_FLOWS,
- q->flows_cnt))
+ q->flows_cnt) ||
+ nla_put_u32(skb, TCA_FQ_CODEL_ECN_TARGET,
+ codel_time_to_us(q->cparams.ecn_target)))
goto nla_put_failure;
nla_nest_end(skb, opts);
--
1.7.9.5
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