* 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
end of thread, other threads:[~2012-01-03 17:52 UTC | newest]
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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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