* Re: BQL + Basic Latency under load results - 100Mbit, GSO/TSO off, pfifo_fast vs SFQ vs QFQ [not found] ` <CAA93jw7bLnHtVnZGN5wVPQZc46XT_B--cY1ocUbnm1AS=J_YHw@mail.gmail.com> @ 2012-01-02 4:33 ` Eric Dumazet 2012-01-02 4:55 ` Eric Dumazet 2012-01-03 17:52 ` David Miller 0 siblings, 2 replies; 5+ messages in thread From: Eric Dumazet @ 2012-01-02 4:33 UTC (permalink / raw) To: Dave Taht Cc: jg, Stephen Hemminger, Juliusz Chroboczek, Kathleen Nichols, netdev Le lundi 02 janvier 2012 à 00:17 +0100, Dave Taht a écrit : > QFQ wins even bigger vs SFQ at 50 iperfs > > http://www.teklibre.com/~d/bloat/pfifo_sfq_vs_qfq_linear50.png > > And I think it's going to win even bigger at 10 Mbit. > Happy new year ! This makes no sense to me for such a low amount of flows, SFQ should perform the same than QFQ :) You dont find out why it is so. Please try following patch : [PATCH net-next] sch_sfq: dont put new flow at the end of flows SFQ enqueue algo puts a new flow _behind_ all pre-existing flows in the circular list. In fact this is probably an old SFQ implementation bug. 100 Mbits = ~8333 full frames per second, or ~8 frames per ms. With 50 flows, it means your "new flow" will have to wait 50 packets being sent before its own packet. Thats the ~6ms. We certainly can change SFQ to give a priority advantage to new flows, so that next dequeued packet is taken from a new flow, not an old one. Reported-by: Dave Taht <dave.taht@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> --- diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c index c23b957..f7f62a5 100644 --- a/net/sched/sch_sfq.c +++ b/net/sched/sch_sfq.c @@ -366,11 +366,11 @@ sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch) if (slot->qlen == 1) { /* The flow is new */ if (q->tail == NULL) { /* It is the first flow */ slot->next = x; + q->tail = slot; } else { slot->next = q->tail->next; q->tail->next = x; } - q->tail = slot; slot->allot = q->scaled_quantum; } if (++sch->q.qlen <= q->limit) ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: BQL + Basic Latency under load results - 100Mbit, GSO/TSO off, pfifo_fast vs SFQ vs QFQ 2012-01-02 4:33 ` BQL + Basic Latency under load results - 100Mbit, GSO/TSO off, pfifo_fast vs SFQ vs QFQ Eric Dumazet @ 2012-01-02 4:55 ` Eric Dumazet 2012-01-02 5:07 ` Eric Dumazet 2012-01-03 17:52 ` David Miller 1 sibling, 1 reply; 5+ messages in thread From: Eric Dumazet @ 2012-01-02 4:55 UTC (permalink / raw) To: Dave Taht Cc: jg, Stephen Hemminger, Juliusz Chroboczek, Kathleen Nichols, netdev Le lundi 02 janvier 2012 à 05:33 +0100, Eric Dumazet a écrit : > Le lundi 02 janvier 2012 à 00:17 +0100, Dave Taht a écrit : > > QFQ wins even bigger vs SFQ at 50 iperfs > > > > http://www.teklibre.com/~d/bloat/pfifo_sfq_vs_qfq_linear50.png > > > > And I think it's going to win even bigger at 10 Mbit. > > > > Happy new year ! > > This makes no sense to me for such a low amount of flows, SFQ should > perform the same than QFQ :) > > You dont find out why it is so. > > > > Please try following patch : > > [PATCH net-next] sch_sfq: dont put new flow at the end of flows > > SFQ enqueue algo puts a new flow _behind_ all pre-existing flows in the > circular list. In fact this is probably an old SFQ implementation bug. > > 100 Mbits = ~8333 full frames per second, or ~8 frames per ms. > > With 50 flows, it means your "new flow" will have to wait 50 packets > being sent before its own packet. Thats the ~6ms. > > We certainly can change SFQ to give a priority advantage to new flows, > so that next dequeued packet is taken from a new flow, not an old one. > > Reported-by: Dave Taht <dave.taht@gmail.com> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> > --- > diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c > index c23b957..f7f62a5 100644 > --- a/net/sched/sch_sfq.c > +++ b/net/sched/sch_sfq.c > @@ -366,11 +366,11 @@ sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch) > if (slot->qlen == 1) { /* The flow is new */ > if (q->tail == NULL) { /* It is the first flow */ > slot->next = x; > + q->tail = slot; > } else { > slot->next = q->tail->next; > q->tail->next = x; > } > - q->tail = slot; > slot->allot = q->scaled_quantum; > } > if (++sch->q.qlen <= q->limit) > I tested this patch with a 50 concurrent netperf workload, and indeed this fixes the problem for me. # ping 192.168.20.108 PING 192.168.20.108 (192.168.20.108) 56(84) bytes of data. 64 bytes from 192.168.20.108: icmp_req=1 ttl=64 time=0.021 ms 64 bytes from 192.168.20.108: icmp_req=2 ttl=64 time=0.011 ms 64 bytes from 192.168.20.108: icmp_req=3 ttl=64 time=0.011 ms 64 bytes from 192.168.20.108: icmp_req=4 ttl=64 time=0.010 ms 64 bytes from 192.168.20.108: icmp_req=5 ttl=64 time=0.010 ms 64 bytes from 192.168.20.108: icmp_req=6 ttl=64 time=0.010 ms # tc -s -d qdisc show dev eth3 qdisc htb 1: root refcnt 18 r2q 10 default 1 direct_packets_stat 0 ver 3.17 Sent 1178661043 bytes 806848 pkt (dropped 9068, overlimits 382834 requeues 3) rate 97748Kbit 8355pps backlog 0b 122p requeues 3 qdisc sfq 10: parent 1:1 limit 127p quantum 1514b flows 127/1024 divisor 1024 Sent 1178661043 bytes 806848 pkt (dropped 17568, overlimits 0 requeues 0) rate 97748Kbit 8355pps backlog 962708b 122p requeues 0 # tc -s -d cl show dev eth3 class htb 1:1 root leaf 10: prio 0 quantum 80000 rate 100000Kbit ceil 100000Kbit burst 40000b/256 mpu 0b overhead 0b cburst 40000b/256 mpu 0b overhead 0b level 0 Sent 1367302331 bytes 935622 pkt (dropped 10494, overlimits 0 requeues 0) rate 100156Kbit 8560pps backlog 0b 125p requeues 0 lended: 207922 borrowed: 0 giants: 0 tokens: -14605 ctokens: -14605 class sfq 10:15 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 14678b 3p requeues 0 allot -3264 class sfq 10:17 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 20Kb 3p requeues 0 allot -6912 class sfq 10:22 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 17508b 2p requeues 0 allot -808 class sfq 10:3c parent 10: (dropped 0, overlimits 0 requeues 0) backlog 17508b 2p requeues 0 allot -4208 class sfq 10:5e parent 10: (dropped 0, overlimits 0 requeues 0) backlog 27Kb 2p requeues 0 allot -6024 class sfq 10:66 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 11716b 2p requeues 0 allot -4856 class sfq 10:8d parent 10: (dropped 0, overlimits 0 requeues 0) backlog 14612b 2p requeues 0 allot 1296 class sfq 10:9b parent 10: (dropped 0, overlimits 0 requeues 0) backlog 7504b 4p requeues 0 allot 1184 class sfq 10:9c parent 10: (dropped 0, overlimits 0 requeues 0) backlog 14612b 2p requeues 0 allot -104 class sfq 10:a9 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 18956b 2p requeues 0 allot -5456 class sfq 10:ab parent 10: (dropped 0, overlimits 0 requeues 0) backlog 14678b 3p requeues 0 allot -88 class sfq 10:ba parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot -624 class sfq 10:c3 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 27710b 3p requeues 0 allot -8440 class sfq 10:ce parent 10: (dropped 0, overlimits 0 requeues 0) backlog 18956b 2p requeues 0 allot -3160 class sfq 10:f2 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 20Kb 3p requeues 0 allot -672 class sfq 10:11c parent 10: (dropped 0, overlimits 0 requeues 0) backlog 5990b 3p requeues 0 allot -712 class sfq 10:17c parent 10: (dropped 0, overlimits 0 requeues 0) backlog 17508b 2p requeues 0 allot -4000 class sfq 10:188 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 16060b 2p requeues 0 allot -6640 class sfq 10:1b9 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 10202b 1p requeues 0 allot 120 class sfq 10:1c2 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 5924b 2p requeues 0 allot 264 class sfq 10:1cb parent 10: (dropped 0, overlimits 0 requeues 0) backlog 19022b 3p requeues 0 allot -2904 class sfq 10:1e5 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 23366b 3p requeues 0 allot -7800 class sfq 10:1f9 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 8984b 4p requeues 0 allot 560 class sfq 10:210 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 17574b 3p requeues 0 allot -384 class sfq 10:231 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 19022b 3p requeues 0 allot 1416 class sfq 10:27c parent 10: (dropped 0, overlimits 0 requeues 0) backlog 20404b 2p requeues 0 allot 752 class sfq 10:289 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 19022b 3p requeues 0 allot 1208 class sfq 10:2a3 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 14612b 2p requeues 0 allot -2592 class sfq 10:2a6 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 19022b 3p requeues 0 allot -5008 class sfq 10:2c7 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 7570b 5p requeues 0 allot -1168 class sfq 10:2d0 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 8820b 2p requeues 0 allot -1088 class sfq 10:2e5 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 20404b 2p requeues 0 allot -10648 class sfq 10:2ec parent 10: (dropped 0, overlimits 0 requeues 0) backlog 13164b 2p requeues 0 allot -1800 class sfq 10:2ee parent 10: (dropped 0, overlimits 0 requeues 0) backlog 20Kb 3p requeues 0 allot -9016 class sfq 10:305 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 10400b 4p requeues 0 allot -872 class sfq 10:318 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 504 class sfq 10:31f parent 10: (dropped 0, overlimits 0 requeues 0) backlog 10400b 4p requeues 0 allot -4024 class sfq 10:328 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 16060b 2p requeues 0 allot -16 class sfq 10:32d parent 10: (dropped 0, overlimits 0 requeues 0) backlog 21918b 3p requeues 0 allot -840 class sfq 10:37d parent 10: (dropped 0, overlimits 0 requeues 0) backlog 14612b 2p requeues 0 allot 432 class sfq 10:3ac parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1224 class sfq 10:3d0 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 20Kb 3p requeues 0 allot -11232 class sfq 10:3d1 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 26262b 3p requeues 0 allot -1832 class sfq 10:3d8 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 5924b 2p requeues 0 allot -512 class sfq 10:3e7 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 29158b 3p requeues 0 allot -10976 class sfq 10:3f0 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 32054b 3p requeues 0 allot -2080 class sfq 10:3f9 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 18956b 2p requeues 0 allot -1704 ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: BQL + Basic Latency under load results - 100Mbit, GSO/TSO off, pfifo_fast vs SFQ vs QFQ 2012-01-02 4:55 ` Eric Dumazet @ 2012-01-02 5:07 ` Eric Dumazet 2012-01-02 5:27 ` Eric Dumazet 0 siblings, 1 reply; 5+ messages in thread From: Eric Dumazet @ 2012-01-02 5:07 UTC (permalink / raw) To: Dave Taht Cc: jg, Stephen Hemminger, Juliusz Chroboczek, Kathleen Nichols, netdev Le lundi 02 janvier 2012 à 05:55 +0100, Eric Dumazet a écrit : > I tested this patch with a 50 concurrent netperf workload, and indeed > this fixes the problem for me. > > # ping 192.168.20.108 > PING 192.168.20.108 (192.168.20.108) 56(84) bytes of data. > 64 bytes from 192.168.20.108: icmp_req=1 ttl=64 time=0.021 ms > 64 bytes from 192.168.20.108: icmp_req=2 ttl=64 time=0.011 ms > 64 bytes from 192.168.20.108: icmp_req=3 ttl=64 time=0.011 ms > 64 bytes from 192.168.20.108: icmp_req=4 ttl=64 time=0.010 ms > 64 bytes from 192.168.20.108: icmp_req=5 ttl=64 time=0.010 ms > 64 bytes from 192.168.20.108: icmp_req=6 ttl=64 time=0.010 ms > Oops, pinging a real machine, not myself I get more realistic numbers :) # ping -c 20 192.168.20.112 PING 192.168.20.112 (192.168.20.112) 56(84) bytes of data. 64 bytes from 192.168.20.112: icmp_req=1 ttl=64 time=0.488 ms 64 bytes from 192.168.20.112: icmp_req=2 ttl=64 time=0.214 ms 64 bytes from 192.168.20.112: icmp_req=3 ttl=64 time=0.696 ms 64 bytes from 192.168.20.112: icmp_req=4 ttl=64 time=0.135 ms 64 bytes from 192.168.20.112: icmp_req=5 ttl=64 time=0.110 ms 64 bytes from 192.168.20.112: icmp_req=6 ttl=64 time=0.401 ms 64 bytes from 192.168.20.112: icmp_req=7 ttl=64 time=0.378 ms 64 bytes from 192.168.20.112: icmp_req=8 ttl=64 time=0.384 ms 64 bytes from 192.168.20.112: icmp_req=9 ttl=64 time=1.03 ms 64 bytes from 192.168.20.112: icmp_req=10 ttl=64 time=0.439 ms 64 bytes from 192.168.20.112: icmp_req=11 ttl=64 time=0.126 ms 64 bytes from 192.168.20.112: icmp_req=12 ttl=64 time=0.093 ms 64 bytes from 192.168.20.112: icmp_req=13 ttl=64 time=0.834 ms 64 bytes from 192.168.20.112: icmp_req=14 ttl=64 time=0.696 ms 64 bytes from 192.168.20.112: icmp_req=15 ttl=64 time=0.776 ms 64 bytes from 192.168.20.112: icmp_req=16 ttl=64 time=0.215 ms 64 bytes from 192.168.20.112: icmp_req=17 ttl=64 time=0.262 ms 64 bytes from 192.168.20.112: icmp_req=18 ttl=64 time=0.554 ms 64 bytes from 192.168.20.112: icmp_req=19 ttl=64 time=0.373 ms 64 bytes from 192.168.20.112: icmp_req=20 ttl=64 time=0.666 ms --- 192.168.20.112 ping statistics --- 20 packets transmitted, 20 received, 0% packet loss, time 19000ms rtt min/avg/max/mdev = 0.093/0.443/1.035/0.264 ms ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: BQL + Basic Latency under load results - 100Mbit, GSO/TSO off, pfifo_fast vs SFQ vs QFQ 2012-01-02 5:07 ` Eric Dumazet @ 2012-01-02 5:27 ` Eric Dumazet 0 siblings, 0 replies; 5+ messages in thread From: Eric Dumazet @ 2012-01-02 5:27 UTC (permalink / raw) To: Dave Taht Cc: jg, Stephen Hemminger, Juliusz Chroboczek, Kathleen Nichols, netdev Le lundi 02 janvier 2012 à 06:07 +0100, Eric Dumazet a écrit : > Le lundi 02 janvier 2012 à 05:55 +0100, Eric Dumazet a écrit : > > > I tested this patch with a 50 concurrent netperf workload, and indeed > > this fixes the problem for me. > > > > # ping 192.168.20.108 > > PING 192.168.20.108 (192.168.20.108) 56(84) bytes of data. > > 64 bytes from 192.168.20.108: icmp_req=1 ttl=64 time=0.021 ms > > 64 bytes from 192.168.20.108: icmp_req=2 ttl=64 time=0.011 ms > > 64 bytes from 192.168.20.108: icmp_req=3 ttl=64 time=0.011 ms > > 64 bytes from 192.168.20.108: icmp_req=4 ttl=64 time=0.010 ms > > 64 bytes from 192.168.20.108: icmp_req=5 ttl=64 time=0.010 ms > > 64 bytes from 192.168.20.108: icmp_req=6 ttl=64 time=0.010 ms > > > > Oops, pinging a real machine, not myself I get more realistic numbers :) > > # ping -c 20 192.168.20.112 > PING 192.168.20.112 (192.168.20.112) 56(84) bytes of data. > 64 bytes from 192.168.20.112: icmp_req=1 ttl=64 time=0.488 ms > 64 bytes from 192.168.20.112: icmp_req=2 ttl=64 time=0.214 ms > 64 bytes from 192.168.20.112: icmp_req=3 ttl=64 time=0.696 ms > 64 bytes from 192.168.20.112: icmp_req=4 ttl=64 time=0.135 ms > 64 bytes from 192.168.20.112: icmp_req=5 ttl=64 time=0.110 ms > 64 bytes from 192.168.20.112: icmp_req=6 ttl=64 time=0.401 ms > 64 bytes from 192.168.20.112: icmp_req=7 ttl=64 time=0.378 ms > 64 bytes from 192.168.20.112: icmp_req=8 ttl=64 time=0.384 ms > 64 bytes from 192.168.20.112: icmp_req=9 ttl=64 time=1.03 ms > 64 bytes from 192.168.20.112: icmp_req=10 ttl=64 time=0.439 ms > 64 bytes from 192.168.20.112: icmp_req=11 ttl=64 time=0.126 ms > 64 bytes from 192.168.20.112: icmp_req=12 ttl=64 time=0.093 ms > 64 bytes from 192.168.20.112: icmp_req=13 ttl=64 time=0.834 ms > 64 bytes from 192.168.20.112: icmp_req=14 ttl=64 time=0.696 ms > 64 bytes from 192.168.20.112: icmp_req=15 ttl=64 time=0.776 ms > 64 bytes from 192.168.20.112: icmp_req=16 ttl=64 time=0.215 ms > 64 bytes from 192.168.20.112: icmp_req=17 ttl=64 time=0.262 ms > 64 bytes from 192.168.20.112: icmp_req=18 ttl=64 time=0.554 ms > 64 bytes from 192.168.20.112: icmp_req=19 ttl=64 time=0.373 ms > 64 bytes from 192.168.20.112: icmp_req=20 ttl=64 time=0.666 ms > > --- 192.168.20.112 ping statistics --- > 20 packets transmitted, 20 received, 0% packet loss, time 19000ms > rtt min/avg/max/mdev = 0.093/0.443/1.035/0.264 ms > And after disabling TSO (as you did in your tests) I get this : (Note my link is Gigabit, so I had to install a HTB shaper to 100Mbit to mimic your workload) # ping -c 20 192.168.20.112 PING 192.168.20.112 (192.168.20.112) 56(84) bytes of data. 64 bytes from 192.168.20.112: icmp_req=1 ttl=64 time=0.113 ms 64 bytes from 192.168.20.112: icmp_req=2 ttl=64 time=0.153 ms 64 bytes from 192.168.20.112: icmp_req=3 ttl=64 time=0.092 ms 64 bytes from 192.168.20.112: icmp_req=4 ttl=64 time=0.095 ms 64 bytes from 192.168.20.112: icmp_req=5 ttl=64 time=0.176 ms 64 bytes from 192.168.20.112: icmp_req=6 ttl=64 time=0.159 ms 64 bytes from 192.168.20.112: icmp_req=7 ttl=64 time=0.169 ms 64 bytes from 192.168.20.112: icmp_req=8 ttl=64 time=0.122 ms 64 bytes from 192.168.20.112: icmp_req=9 ttl=64 time=0.148 ms 64 bytes from 192.168.20.112: icmp_req=10 ttl=64 time=0.123 ms 64 bytes from 192.168.20.112: icmp_req=11 ttl=64 time=0.186 ms 64 bytes from 192.168.20.112: icmp_req=12 ttl=64 time=0.210 ms 64 bytes from 192.168.20.112: icmp_req=13 ttl=64 time=0.142 ms 64 bytes from 192.168.20.112: icmp_req=14 ttl=64 time=0.134 ms 64 bytes from 192.168.20.112: icmp_req=15 ttl=64 time=0.092 ms 64 bytes from 192.168.20.112: icmp_req=16 ttl=64 time=0.187 ms 64 bytes from 192.168.20.112: icmp_req=17 ttl=64 time=0.123 ms 64 bytes from 192.168.20.112: icmp_req=18 ttl=64 time=0.159 ms 64 bytes from 192.168.20.112: icmp_req=19 ttl=64 time=0.142 ms 64 bytes from 192.168.20.112: icmp_req=20 ttl=64 time=0.207 ms --- 192.168.20.112 ping statistics --- 20 packets transmitted, 20 received, 0% packet loss, time 18999ms rtt min/avg/max/mdev = 0.092/0.146/0.210/0.037 ms # tc -s -d cl show dev eth3 class htb 1:1 root leaf 10: prio 0 quantum 80000 rate 100000Kbit ceil 100000Kbit burst 40000b/256 mpu 0b overhead 0b cburst 40000b/256 mpu 0b overhead 0b level 0 Sent 4569893772 bytes 3107171 pkt (dropped 43457, overlimits 0 requeues 0) rate 75836Kbit 6315pps backlog 0b 127p requeues 0 lended: 1204316 borrowed: 0 giants: 0 tokens: -1892 ctokens: -1892 class sfq 10:1b parent 10: (dropped 0, overlimits 0 requeues 0) backlog 3028b 2p requeues 0 allot 1520 class sfq 10:25 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:34 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:48 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:4b parent 10: (dropped 0, overlimits 0 requeues 0) backlog 3028b 2p requeues 0 allot -448 class sfq 10:4c parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:68 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:96 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:a9 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 3028b 2p requeues 0 allot 1520 class sfq 10:c8 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:ca parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:112 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:11a parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:149 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:150 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 3028b 2p requeues 0 allot 1520 class sfq 10:16b parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:171 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:185 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:19f parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:1ac parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:1bb parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:1bf parent 10: (dropped 0, overlimits 0 requeues 0) backlog 3028b 2p requeues 0 allot 1520 class sfq 10:1dc parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:1e7 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 3028b 2p requeues 0 allot 1520 class sfq 10:1f1 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:201 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:20f parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:216 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:21d parent 10: (dropped 0, overlimits 0 requeues 0) backlog 3028b 2p requeues 0 allot 1520 class sfq 10:22a parent 10: (dropped 0, overlimits 0 requeues 0) backlog 3028b 2p requeues 0 allot 1520 class sfq 10:22e parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:263 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:2d4 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:306 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:307 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:344 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:346 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 3028b 2p requeues 0 allot 1520 class sfq 10:34f parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:359 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:36f parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:385 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:3a0 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:3a4 parent 10: (dropped 0, overlimits 0 requeues 0) backlog 1514b 1p requeues 0 allot 0 class sfq 10:3ac parent 10: (dropped 0, overlimits 0 requeues 0) backlog 3028b 2p requeues 0 allot 1520 class sfq 10:3ee parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 class sfq 10:3fe parent 10: (dropped 0, overlimits 0 requeues 0) backlog 4542b 3p requeues 0 allot 1520 ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: BQL + Basic Latency under load results - 100Mbit, GSO/TSO off, pfifo_fast vs SFQ vs QFQ 2012-01-02 4:33 ` BQL + Basic Latency under load results - 100Mbit, GSO/TSO off, pfifo_fast vs SFQ vs QFQ Eric Dumazet 2012-01-02 4:55 ` Eric Dumazet @ 2012-01-03 17:52 ` David Miller 1 sibling, 0 replies; 5+ messages in thread From: David Miller @ 2012-01-03 17:52 UTC (permalink / raw) To: eric.dumazet; +Cc: dave.taht, jg, shemminger, jch, nichols, netdev From: Eric Dumazet <eric.dumazet@gmail.com> Date: Mon, 02 Jan 2012 05:33:31 +0100 > [PATCH net-next] sch_sfq: dont put new flow at the end of flows > > SFQ enqueue algo puts a new flow _behind_ all pre-existing flows in the > circular list. In fact this is probably an old SFQ implementation bug. > > 100 Mbits = ~8333 full frames per second, or ~8 frames per ms. > > With 50 flows, it means your "new flow" will have to wait 50 packets > being sent before its own packet. Thats the ~6ms. > > We certainly can change SFQ to give a priority advantage to new flows, > so that next dequeued packet is taken from a new flow, not an old one. > > Reported-by: Dave Taht <dave.taht@gmail.com> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Applied, thanks Eric. ^ permalink raw reply [flat|nested] 5+ messages in thread
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2012-01-02 4:33 ` BQL + Basic Latency under load results - 100Mbit, GSO/TSO off, pfifo_fast vs SFQ vs QFQ Eric Dumazet
2012-01-02 4:55 ` Eric Dumazet
2012-01-02 5:07 ` Eric Dumazet
2012-01-02 5:27 ` Eric Dumazet
2012-01-03 17:52 ` David Miller
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