linux/net
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
..
9p for-linus-3.12-merge minor 9p fixes and tweaks for 3.12 merge window 2013-09-11 12:34:13 -07:00
802 mrp: add periodictimer to allow retries when packets get lost 2013-09-23 16:53:52 -04:00
8021q net: vlan: inherit addr_assign_type along with dev_addr 2013-09-03 20:57:49 -04:00
appletalk net: proc_fs: trivial: print UIDs as unsigned int 2013-08-15 14:37:46 -07:00
atm
ax25 net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
batman-adv batman-adv: set the TAG flag for the vid passed to BLA 2013-09-17 21:15:16 +02:00
bluetooth Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless into for-davem 2013-09-27 13:11:17 -04:00
bridge bridge: fix NULL pointer deref of br_port_get_rcu 2013-09-15 22:03:33 -04:00
caif caif: Add missing braces to multiline if in cfctrl_linkup_request 2013-09-05 14:31:02 -04:00
can can: gw: add a per rule limitation of frame hops 2013-08-29 22:58:24 +02:00
ceph Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2013-09-19 12:50:37 -05:00
core net: flow_dissector: fix thoff for IPPROTO_AH 2013-09-30 15:32:05 -04:00
dcb
dccp net:dccp: do not report ICMP redirects to user space 2013-09-18 12:33:44 -04:00
decnet net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
dns_resolver net: strict_strtoul is obsolete, use kstrtoul instead 2013-07-12 16:09:14 -07:00
dsa net: dsa: inherit addr_assign_type along with dev_addr 2013-09-03 20:57:49 -04:00
ethernet net: Fix sysfs_format_mac() code duplication. 2013-07-16 17:09:22 -07:00
ieee802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-09-05 14:54:29 -07:00
ipv4 ip_tunnel: Remove double unregister of the fallback device 2013-10-01 12:42:16 -04:00
ipv6 ip6tnl: allow to use rtnl ops on fb tunnel 2013-10-01 12:55:53 -04:00
ipx net: proc_fs: trivial: print UIDs as unsigned int 2013-08-15 14:37:46 -07:00
irda net/irda: fixed style issues in irttp 2013-07-19 17:34:40 -07:00
iucv net: delete __cpuinit usage from all net files 2013-07-14 19:36:58 -04:00
key xfrm: Remove rebundant address family checking 2013-08-07 10:12:58 +02:00
l2tp l2tp: make datapath resilient to packet loss when sequence numbers enabled 2013-07-02 16:33:25 -07:00
lapb net/lapb: re-send packets on timeout 2013-09-23 16:52:45 -04:00
llc llc: Use normal etherdevice.h tests 2013-09-03 22:34:47 -04:00
mac80211 Merge branch 'for-john' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next 2013-08-28 13:51:40 -04:00
mac802154
mpls
netfilter Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2013-10-01 12:39:35 -04:00
netlabel netlabel: use domain based selectors when address based selectors are not available 2013-08-02 16:57:01 -07:00
netlink net: netlink: filter particular protocols from analyzers 2013-09-06 14:43:48 -04:00
netrom net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
nfc NFC: Update secure element state 2013-08-14 01:13:40 +02:00
openvswitch net: ovs: flow: fix potential illegal memory access in __parse_flow_nlattrs 2013-09-11 16:09:58 -04:00
packet net: packet: use reciprocal_divide in fanout_demux_hash 2013-08-29 16:43:29 -04:00
phonet net: proc_fs: trivial: print UIDs as unsigned int 2013-08-15 14:37:46 -07:00
rds net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
rfkill Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-09-05 14:54:29 -07:00
rose net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
rxrpc
sched pkt_sched: fq: rate limiting improvements 2013-10-01 13:00:38 -04:00
sctp net: sctp: rfc4443: do not report ICMP redirects to user space 2013-09-16 21:40:15 -04:00
sunrpc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-09-12 15:01:38 -07:00
tipc tipc: set sk_err correctly when connection fails 2013-08-30 16:06:57 -04:00
unix af_unix: fix bug on large send() 2013-08-11 22:02:36 -07:00
vmw_vsock Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-08-16 15:37:26 -07:00
wimax
wireless Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-09-05 14:54:29 -07:00
x25 x25: add a sanity check parsing X.25 facilities 2013-09-04 00:27:27 -04:00
xfrm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-09-05 14:58:52 -04:00
compat.c net: Unbreak compat_sys_{send,recv}msg 2013-06-06 11:52:14 -07:00
Kconfig Remove GENERIC_HARDIRQ config option 2013-09-13 15:09:52 +02:00
Makefile
nonet.c
socket.c Merge git://git.kvack.org/~bcrl/aio-next 2013-09-13 10:55:58 -07:00
sysctl_net.c