Eric Dumazet 0eab5eb7a3 pkt_sched: fq: rate limiting improvements ... FQ rate limiting suffers from two problems, reported by Steinar : 1) FQ enforces a delay when flow quantum is exhausted in order to reduce cpu overhead. But if packets are small, current delay computation is slightly wrong, and observed rates can be too high. Steinar had this problem because he disabled TSO and GSO, and default FQ quantum is 2*1514. (Of course, I wish recent TSO auto sizing changes will help to not having to disable TSO in the first place) 2) maxrate was not used for forwarded flows (skbs not attached to a socket) Tested: tc qdisc add dev eth0 root est 1sec 4sec fq maxrate 8Mbit netperf -H lpq84 -l 1000 & sleep 10 ; tc -s qdisc show dev eth0 qdisc fq 8003: root refcnt 32 limit 10000p flow_limit 100p buckets 1024 quantum 3028 initial_quantum 15140 maxrate 8000Kbit Sent 16819357 bytes 11258 pkt (dropped 0, overlimits 0 requeues 0) rate 7831Kbit 653pps backlog 7570b 5p requeues 0 44 flows (43 inactive, 1 throttled), next packet delay 2977352 ns 0 gc, 0 highprio, 5545 throttled lpq83:~# tcpdump -p -i eth0 host lpq84 -c 12 09:02:52.079484 IP lpq83 > lpq84: . 1389536928:1389538376(1448) ack 3808678021 win 457 <nop,nop,timestamp 961812 572609068> 09:02:52.079499 IP lpq83 > lpq84: . 1448:2896(1448) ack 1 win 457 <nop,nop,timestamp 961812 572609068> 09:02:52.079906 IP lpq84 > lpq83: . ack 2896 win 16384 <nop,nop,timestamp 572609080 961812> 09:02:52.082568 IP lpq83 > lpq84: . 2896:4344(1448) ack 1 win 457 <nop,nop,timestamp 961815 572609071> 09:02:52.082581 IP lpq83 > lpq84: . 4344:5792(1448) ack 1 win 457 <nop,nop,timestamp 961815 572609071> 09:02:52.083017 IP lpq84 > lpq83: . ack 5792 win 16384 <nop,nop,timestamp 572609083 961815> 09:02:52.085678 IP lpq83 > lpq84: . 5792:7240(1448) ack 1 win 457 <nop,nop,timestamp 961818 572609074> 09:02:52.085693 IP lpq83 > lpq84: . 7240:8688(1448) ack 1 win 457 <nop,nop,timestamp 961818 572609074> 09:02:52.086117 IP lpq84 > lpq83: . ack 8688 win 16384 <nop,nop,timestamp 572609086 961818> 09:02:52.088792 IP lpq83 > lpq84: . 8688:10136(1448) ack 1 win 457 <nop,nop,timestamp 961821 572609077> 09:02:52.088806 IP lpq83 > lpq84: . 10136:11584(1448) ack 1 win 457 <nop,nop,timestamp 961821 572609077> 09:02:52.089217 IP lpq84 > lpq83: . ack 11584 win 16384 <nop,nop,timestamp 572609090 961821> Reported-by: Steinar H. Gunderson <sesse@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2013-10-01 13:00:38 -04:00
..
act_api.c
act_csum.c
act_gact.c
act_ipt.c
act_mirred.c
act_nat.c
act_pedit.c
act_police.c
act_simple.c
act_skbedit.c
cls_api.c
cls_basic.c
cls_cgroup.c	cgroup: make cgroup_taskset deal with cgroup_subsys_state instead of cgroup	2013-08-08 20:11:27 -04:00
cls_flow.c
cls_fw.c
cls_route.c
cls_rsvp6.c
cls_rsvp.c
cls_rsvp.h
cls_tcindex.c
cls_u32.c
em_canid.c
em_cmp.c
em_ipset.c
em_meta.c
em_nbyte.c
em_text.c
em_u32.c
ematch.c
Kconfig	pkt_sched: fq: Fair Queue packet scheduler	2013-08-29 21:38:31 -04:00
Makefile	pkt_sched: fq: Fair Queue packet scheduler	2013-08-29 21:38:31 -04:00
sch_api.c	qdisc: fix build with !CONFIG_NET_SCHED	2013-08-31 18:09:45 -04:00
sch_atm.c	net_sched: info leak in atm_tc_dump_class()	2013-07-31 15:04:19 -07:00
sch_blackhole.c
sch_cbq.c	net_sched: Fix stack info leak in cbq_dump_wrr().	2013-07-30 00:16:21 -07:00
sch_choke.c	treewide: Add __GFP_NOWARN to k.alloc calls with v.alloc fallbacks	2013-08-20 13:06:40 +02:00
sch_codel.c
sch_drr.c
sch_dsmark.c
sch_fifo.c
sch_fq_codel.c
sch_fq.c	pkt_sched: fq: rate limiting improvements	2013-10-01 13:00:38 -04:00
sch_generic.c	qdisc: fix build with !CONFIG_NET_SCHED	2013-08-31 18:09:45 -04:00
sch_gred.c
sch_hfsc.c
sch_htb.c	net_sched: htb: fix a typo in htb_change_class()	2013-09-11 17:16:22 -04:00
sch_ingress.c
sch_mq.c	qdisc: allow setting default queuing discipline	2013-08-31 00:32:32 -04:00
sch_mqprio.c	qdisc: allow setting default queuing discipline	2013-08-31 00:32:32 -04:00
sch_multiq.c
sch_netem.c	netem: Introduce skb_orphan_partial() helper	2013-07-31 14:59:49 -07:00
sch_plug.c
sch_prio.c
sch_qfq.c	pkt_sched: sch_qfq: remove a source of high packet delay/jitter	2013-07-18 13:02:00 -07:00
sch_red.c
sch_sfb.c
sch_sfq.c
sch_tbf.c
sch_teql.c