alistair23-linux/net
Eric Dumazet 76e3cc126b codel: Controlled Delay AQM
An implementation of CoDel AQM, from Kathleen Nichols and Van Jacobson.

http://queue.acm.org/detail.cfm?id=2209336

This AQM main input is no longer queue size in bytes or packets, but the
delay packets stay in (FIFO) queue.

As we don't have infinite memory, we still can drop packets in enqueue()
in case of massive load, but mean of CoDel is to drop packets in
dequeue(), using a control law based on two simple parameters :

target : target sojourn time (default 5ms)
interval : width of moving time window (default 100ms)

Based on initial work from Dave Taht.

Refactored to help future codel inclusion as a plugin for other linux
qdisc (FQ_CODEL, ...), like RED.

include/net/codel.h contains codel algorithm as close as possible than
Kathleen reference.

net/sched/sch_codel.c contains the linux qdisc specific glue.

Separate structures permit a memory efficient implementation of fq_codel
(to be sent as a separate work) : Each flow has its own struct
codel_vars.

timestamps are taken at enqueue() time with 1024 ns precision, allowing
a range of 2199 seconds in queue, and 100Gb links support. iproute2 uses
usec as base unit.

Selected packets are dropped, unless ECN is enabled and packets can get
ECN mark instead.

Tested from 2Mb to 10Gb speeds with no particular problems, on ixgbe and
tg3 drivers (BQL enabled).

Usage: tc qdisc ... codel [ limit PACKETS ] [ target TIME ]
                          [ interval TIME ] [ ecn ]

qdisc codel 10: parent 1:1 limit 2000p target 3.0ms interval 60.0ms ecn
 Sent 13347099587 bytes 8815805 pkt (dropped 0, overlimits 0 requeues 0)
 rate 202365Kbit 16708pps backlog 113550b 75p requeues 0
  count 116 lastcount 98 ldelay 4.3ms dropping drop_next 816us
  maxpacket 1514 ecn_mark 84399 drop_overlimit 0

CoDel must be seen as a base module, and should be used keeping in mind
there is still a FIFO queue. So a typical setup will probably need a
hierarchy of several qdiscs and packet classifiers to be able to meet
whatever constraints a user might have.

One possible example would be to use fq_codel, which combines Fair
Queueing and CoDel, in replacement of sfq / sfq_red.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Dave Taht <dave.taht@bufferbloat.net>
Cc: Kathleen Nichols <nichols@pollere.com>
Cc: Van Jacobson <van@pollere.net>
Cc: Tom Herbert <therbert@google.com>
Cc: Matt Mathis <mattmathis@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-10 23:35:02 -04:00
..
9p net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
802 802: Convert compare_ether_addr to ether_addr_equal 2012-05-09 20:49:17 -04:00
8021q 8021q: Convert compare_ether_addr to ether_addr_equal 2012-05-09 20:49:17 -04:00
appletalk net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
atm atm: Convert compare_ether_addr to ether_addr_equal 2012-05-09 20:49:17 -04:00
ax25 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-04-23 23:15:17 -04:00
batman-adv batman-adv: skip the window protection test when the originator has no neighbours 2012-04-18 09:54:02 +02:00
bluetooth bluetooth: Convert compare_ether_addr to ether_addr_equal 2012-05-09 20:49:18 -04:00
bridge bridge: Convert compare_ether_addr to ether_addr_equal 2012-05-09 20:49:17 -04:00
caif net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
can can: fix sparse warning for cgw_list 2012-04-16 21:08:18 +02:00
ceph crush: include header for global symbols 2012-04-27 00:03:34 -04:00
core ethtool: Extend the ethtool API to obtain plugin module eeprom data 2012-05-10 02:22:17 +01:00
dcb net: dcb: add CEE notify calls 2012-04-25 19:47:17 -04:00
dccp net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
decnet net decnet: Convert to use register_net_sysctl 2012-04-20 21:22:29 -04:00
dns_resolver net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
dsa dsa: Convert compare_ether_addr to ether_addr_equal 2012-05-09 20:49:19 -04:00
econet sock: Introduce named constants for sk_reuse 2012-04-21 15:52:25 -04:00
ethernet net, drivers/net: Convert compare_ether_addr_64bits to ether_addr_equal_64bits 2012-05-10 23:33:01 -04:00
ieee802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-05-07 23:35:40 -04:00
ipv4 tcp: Out-line tcp_try_rmem_schedule 2012-05-10 23:24:36 -04:00
ipv6 netfilter: ip6_tables: add flags parameter to ipv6_find_hdr() 2012-05-09 12:53:47 +02:00
ipx net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
irda net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
iucv Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2012-03-22 18:15:32 -07:00
key net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
l2tp l2tp: fix data packet sequence number handling 2012-05-10 23:27:34 -04:00
lapb Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
llc net: add a limit parameter to sk_add_backlog() 2012-04-23 22:28:28 -04:00
mac80211 mac80211: Convert compare_ether_addr to ether_addr_equal by hand 2012-05-09 20:49:18 -04:00
netfilter netfilter: Convert compare_ether_addr to ether_addr_equal 2012-05-09 20:49:18 -04:00
netlabel netlabel: use GFP flags from caller instead of GFP_ATOMIC 2012-03-22 19:29:57 -04:00
netlink af_netlink: drop_monitor/dropwatch friendly 2012-04-24 00:35:14 -04:00
netrom net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
nfc Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next into for-davem 2012-04-18 14:27:48 -04:00
openvswitch net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
packet af_packet: packet_getsockopt() cleanup 2012-04-21 16:36:42 -04:00
phonet net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
rds sock: Introduce named constants for sk_reuse 2012-04-21 15:52:25 -04:00
rfkill device.h: cleanup users outside of linux/include (C files) 2012-03-11 14:27:37 -04:00
rose net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
rxrpc net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
sched codel: Controlled Delay AQM 2012-05-10 23:35:02 -04:00
sctp net: add a limit parameter to sk_add_backlog() 2012-04-23 22:28:28 -04:00
sunrpc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-05-07 23:35:40 -04:00
tipc tipc: compress out gratuitous extra carriage returns 2012-04-30 15:53:56 -04:00
unix net: sock_diag_handler structs can be const 2012-04-25 20:46:59 -04:00
wanrouter wanrouter: Remove kernel_lock annotations 2011-11-07 13:27:30 -05:00
wimax net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
wireless wireless: Convert compare_ether_addr to ether_addr_equal by hand 2012-05-09 20:49:19 -04:00
x25 net: add a limit parameter to sk_add_backlog() 2012-04-23 22:28:28 -04:00
xfrm net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
compat.c net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
Kconfig net: Add Open vSwitch kernel components. 2011-12-03 09:35:17 -08:00
Makefile net: Add Open vSwitch kernel components. 2011-12-03 09:35:17 -08:00
nonet.c
socket.c net: change big iov allocations 2012-04-21 16:24:20 -04:00
sysctl_net.c net: Remove register_net_sysctl_table 2012-04-20 21:22:30 -04:00