From e288e1bd3210c2025f6fc0dd9c338ea9dbf04bca Mon Sep 17 00:00:00 2001 From: Kevin Darbyshire-Bryant Date: Sat, 7 May 2016 09:57:18 +0100 Subject: [PATCH] kernel: fq_codel match flows_cnt to limit sizing OpenWRT changed the default fq_codel sch->limit from 10240 to 1024, without also adjusting q->flows_cnt. Eric Dumazet explains below that you must also adjust the buckets (q->flows_cnt) for this not to break. Eric explains: Limit of 1024 packets and 1024 flows is not wise I think. (If all buckets are in use, each bucket has a virtual queue of 1 packet, which is almost the same than having no queue at all) I suggest to have at least 8 packets per bucket, to let Codel have a chance to trigger. So you could either reduce number of buckets to 128 (if memory is tight), or increase limit to 8192. flows_cnt is now set to 1024/8=128 Signed-off-by: Kevin Darbyshire-Bryant --- .../linux/generic/patches-3.18/660-fq_codel_defaults.patch | 6 ++++-- .../linux/generic/patches-4.1/660-fq_codel_defaults.patch | 6 ++++-- .../linux/generic/patches-4.4/660-fq_codel_defaults.patch | 6 ++++-- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/target/linux/generic/patches-3.18/660-fq_codel_defaults.patch b/target/linux/generic/patches-3.18/660-fq_codel_defaults.patch index 8c99e62cece..e0f73dedb95 100644 --- a/target/linux/generic/patches-3.18/660-fq_codel_defaults.patch +++ b/target/linux/generic/patches-3.18/660-fq_codel_defaults.patch @@ -1,11 +1,13 @@ --- a/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c -@@ -387,7 +387,7 @@ static int fq_codel_init(struct Qdisc *s +@@ -387,8 +387,8 @@ static int fq_codel_init(struct Qdisc *s struct fq_codel_sched_data *q = qdisc_priv(sch); int i; - sch->limit = 10*1024; +- q->flows_cnt = 1024; + sch->limit = 1024; - q->flows_cnt = 1024; ++ q->flows_cnt = 128; q->quantum = psched_mtu(qdisc_dev(sch)); q->perturbation = prandom_u32(); + INIT_LIST_HEAD(&q->new_flows); diff --git a/target/linux/generic/patches-4.1/660-fq_codel_defaults.patch b/target/linux/generic/patches-4.1/660-fq_codel_defaults.patch index 8c99e62cece..e0f73dedb95 100644 --- a/target/linux/generic/patches-4.1/660-fq_codel_defaults.patch +++ b/target/linux/generic/patches-4.1/660-fq_codel_defaults.patch @@ -1,11 +1,13 @@ --- a/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c -@@ -387,7 +387,7 @@ static int fq_codel_init(struct Qdisc *s +@@ -387,8 +387,8 @@ static int fq_codel_init(struct Qdisc *s struct fq_codel_sched_data *q = qdisc_priv(sch); int i; - sch->limit = 10*1024; +- q->flows_cnt = 1024; + sch->limit = 1024; - q->flows_cnt = 1024; ++ q->flows_cnt = 128; q->quantum = psched_mtu(qdisc_dev(sch)); q->perturbation = prandom_u32(); + INIT_LIST_HEAD(&q->new_flows); diff --git a/target/linux/generic/patches-4.4/660-fq_codel_defaults.patch b/target/linux/generic/patches-4.4/660-fq_codel_defaults.patch index cf4ff6fb186..5d99cd7fb4f 100644 --- a/target/linux/generic/patches-4.4/660-fq_codel_defaults.patch +++ b/target/linux/generic/patches-4.4/660-fq_codel_defaults.patch @@ -1,11 +1,13 @@ --- a/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c -@@ -412,7 +412,7 @@ static int fq_codel_init(struct Qdisc *s +@@ -412,8 +412,8 @@ static int fq_codel_init(struct Qdisc *s struct fq_codel_sched_data *q = qdisc_priv(sch); int i; - sch->limit = 10*1024; +- q->flows_cnt = 1024; + sch->limit = 1024; - q->flows_cnt = 1024; ++ q->flows_cnt = 128; q->quantum = psched_mtu(qdisc_dev(sch)); q->perturbation = prandom_u32(); + INIT_LIST_HEAD(&q->new_flows);