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Eric Dumazet 4b549a2ef4 fq_codel: Fair Queue Codel AQM 
Fair Queue Codel packet scheduler

Principles :

- Packets are classified (internal classifier or external) on flows.
- This is a Stochastic model (as we use a hash, several flows might
                              be hashed on same slot)
- Each flow has a CoDel managed queue.
- Flows are linked onto two (Round Robin) lists,
  so that new flows have priority on old ones.

- For a given flow, packets are not reordered (CoDel uses a FIFO)
- head drops only.
- ECN capability is on by default.
- Very low memory footprint (64 bytes per flow)

tc qdisc ... fq_codel [ limit PACKETS ] [ flows number ]
                      [ target TIME ] [ interval TIME ] [ noecn ]
                      [ quantum BYTES ]

defaults : 1024 flows, 10240 packets limit, quantum : device MTU
           target : 5ms (CoDel default)
           interval : 100ms (CoDel default)

Impressive results on load :

class htb 1:1 root leaf 10: prio 0 quantum 1514 rate 200000Kbit ceil 200000Kbit burst 1475b/8 mpu 0b overhead 0b cburst 1475b/8 mpu 0b overhead 0b level 0
 Sent 43304920109 bytes 33063109 pkt (dropped 0, overlimits 0 requeues 0)
 rate 201691Kbit 28595pps backlog 0b 312p requeues 0
 lended: 33063109 borrowed: 0 giants: 0
 tokens: -912 ctokens: -912

class fq_codel 10:1735 parent 10:
 (dropped 1292, overlimits 0 requeues 0)
 backlog 15140b 10p requeues 0
  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
class fq_codel 10:4524 parent 10:
 (dropped 1291, overlimits 0 requeues 0)
 backlog 16654b 11p requeues 0
  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
class fq_codel 10:4e74 parent 10:
 (dropped 1290, overlimits 0 requeues 0)
 backlog 6056b 4p requeues 0
  deficit 1514 count 1 lastcount 1 ldelay 6.4ms dropping drop_next 92.0ms
class fq_codel 10:628a parent 10:
 (dropped 1289, overlimits 0 requeues 0)
 backlog 7570b 5p requeues 0
  deficit 1514 count 1 lastcount 1 ldelay 5.4ms dropping drop_next 90.9ms
class fq_codel 10:a4b3 parent 10:
 (dropped 302, overlimits 0 requeues 0)
 backlog 16654b 11p requeues 0
  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
class fq_codel 10:c3c2 parent 10:
 (dropped 1284, overlimits 0 requeues 0)
 backlog 13626b 9p requeues 0
  deficit 1514 count 1 lastcount 1 ldelay 5.9ms
class fq_codel 10:d331 parent 10:
 (dropped 299, overlimits 0 requeues 0)
 backlog 15140b 10p requeues 0
  deficit 1514 count 1 lastcount 1 ldelay 7.0ms
class fq_codel 10:d526 parent 10:
 (dropped 12160, overlimits 0 requeues 0)
 backlog 35870b 211p requeues 0
  deficit 1508 count 12160 lastcount 1 ldelay 15.3ms dropping drop_next 247us
class fq_codel 10:e2c6 parent 10:
 (dropped 1288, overlimits 0 requeues 0)
 backlog 15140b 10p requeues 0
  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
class fq_codel 10:eab5 parent 10:
 (dropped 1285, overlimits 0 requeues 0)
 backlog 16654b 11p requeues 0
  deficit 1514 count 1 lastcount 1 ldelay 5.9ms
class fq_codel 10:f220 parent 10:
 (dropped 1289, overlimits 0 requeues 0)
 backlog 15140b 10p requeues 0
  deficit 1514 count 1 lastcount 1 ldelay 7.1ms

qdisc htb 1: root refcnt 6 r2q 10 default 1 direct_packets_stat 0 ver 3.17
 Sent 43331086547 bytes 33092812 pkt (dropped 0, overlimits 66063544 requeues 71)
 rate 201697Kbit 28602pps backlog 0b 260p requeues 71
qdisc fq_codel 10: parent 1:1 limit 10240p flows 65536 target 5.0ms interval 100.0ms ecn
 Sent 43331086547 bytes 33092812 pkt (dropped 949359, overlimits 0 requeues 0)
 rate 201697Kbit 28602pps backlog 189352b 260p requeues 0
  maxpacket 1514 drop_overlimit 0 new_flow_count 5582 ecn_mark 125593
  new_flows_len 0 old_flows_len 11

PING 172.30.42.18 (172.30.42.18) 56(84) bytes of data.
64 bytes from 172.30.42.18: icmp_req=1 ttl=64 time=0.227 ms
64 bytes from 172.30.42.18: icmp_req=2 ttl=64 time=0.165 ms
64 bytes from 172.30.42.18: icmp_req=3 ttl=64 time=0.166 ms
64 bytes from 172.30.42.18: icmp_req=4 ttl=64 time=0.151 ms
64 bytes from 172.30.42.18: icmp_req=5 ttl=64 time=0.164 ms
64 bytes from 172.30.42.18: icmp_req=6 ttl=64 time=0.172 ms
64 bytes from 172.30.42.18: icmp_req=7 ttl=64 time=0.175 ms
64 bytes from 172.30.42.18: icmp_req=8 ttl=64 time=0.183 ms
64 bytes from 172.30.42.18: icmp_req=9 ttl=64 time=0.158 ms
64 bytes from 172.30.42.18: icmp_req=10 ttl=64 time=0.200 ms

10 packets transmitted, 10 received, 0% packet loss, time 8999ms
rtt min/avg/max/mdev = 0.151/0.176/0.227/0.022 ms

Much better than SFQ because of priority given to new flows, and fast
path dirtying less cache lines.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-12 15:53:42 -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: add contributor name 2012-05-11 13:56:08 +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 net/ipv6/af_inet6.c: checkpatch cleanup 2012-05-11 18:04:53 -04:00
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 fq_codel: Fair Queue Codel AQM 2012-05-12 15:53:42 -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
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