linux/net/ipv4
Eric Dumazet 43e122b014 tcp: refine pacing rate determination
When TCP pacing was added back in linux-3.12, we chose
to apply a fixed ratio of 200 % against current rate,
to allow probing for optimal throughput even during
slow start phase, where cwnd can be doubled every other gRTT.

At Google, we found it was better applying a different ratio
while in Congestion Avoidance phase.
This ratio was set to 120 %.

We've used the normal tcp_in_slow_start() helper for a while,
then tuned the condition to select the conservative ratio
as soon as cwnd >= ssthresh/2 :

- After cwnd reduction, it is safer to ramp up more slowly,
  as we approach optimal cwnd.
- Initial ramp up (ssthresh == INFINITY) still allows doubling
  cwnd every other RTT.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-25 11:33:54 -07:00
..
netfilter Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-08-21 06:09:05 +02:00
af_inet.c inet: Move VRF table lookup to inlined function 2015-08-17 15:58:57 -07:00
ah4.c ipsec: Remove obsolete MAX_AH_AUTH_LEN 2014-09-18 10:54:36 +02:00
arp.c net: Fix up inet_addr_type checks 2015-08-13 22:43:21 -07:00
cipso_ipv4.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
datagram.c net: Set sk_txhash from a random number 2015-07-29 22:44:04 -07:00
devinet.c net/ipv4: suppress NETDEV_UP notification on address lifetime update 2015-07-28 23:38:13 -07:00
esp4.c esp4: Switch to new AEAD interface 2015-05-28 11:23:20 +08:00
fib_frontend.c net: Add routes to the table associated with the device 2015-08-13 22:43:21 -07:00
fib_lookup.h ipv4: consider TOS in fib_select_default 2015-07-24 22:46:11 -07:00
fib_rules.c net: ipv4 sysctl option to ignore routes when nexthop link is down 2015-06-24 02:15:54 -07:00
fib_semantics.c lwt: Add cfg argument to build_state 2015-08-24 10:34:40 -07:00
fib_trie.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-08-21 11:44:04 -07:00
fou.c fou: Do WARN_ON_ONCE in gue_gro_receive for bad proto callbacks 2015-08-23 15:59:56 -07:00
geneve_core.c geneve_core: identify as driver library in modules description 2015-05-13 15:59:13 -04:00
gre_demux.c gre: Remove support for sharing GRE protocol hook. 2015-08-10 14:03:54 -07:00
gre_offload.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
icmp.c vrf: vrf_master_ifindex_rcu is not always called with rcu read lock 2015-08-19 22:13:20 -07:00
igmp.c net: fix wrong skb_get() usage / crash in IGMP/MLD parsing code 2015-08-13 17:08:39 -07:00
inet_connection_sock.c inet: fix potential deadlock in reqsk_queue_unlink() 2015-08-13 22:46:22 -07:00
inet_diag.c net: inet_diag: always export IPV6_V6ONLY sockopt for listening sockets 2015-07-10 23:25:24 -07:00
inet_fragment.c inet: frags: remove INET_FRAG_EVICTED and use list_evictor for the test 2015-07-26 21:00:15 -07:00
inet_hashtables.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-07-23 00:41:16 -07:00
inet_lro.c
inet_timewait_sock.c inet: inet_twsk_deschedule factorization 2015-07-09 15:12:20 -07:00
inetpeer.c inet: remove dead inetpeer sequence code 2014-09-08 16:42:42 -07:00
ip_forward.c ip: reject too-big defragmented DF-skb when forwarding 2015-05-25 00:08:48 -04:00
ip_fragment.c net: frags: Add VRF device index to cache and lookup 2015-08-13 22:43:21 -07:00
ip_gre.c route: move lwtunnel state to dst_entry 2015-08-20 15:42:36 -07:00
ip_input.c dst: Metadata destinations 2015-07-21 10:39:05 -07:00
ip_options.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
ip_output.c net: Use VRF index for oif in ip_send_unicast_reply 2015-08-13 22:43:21 -07:00
ip_sockglue.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-24 02:58:51 -07:00
ip_tunnel_core.c lwt: Add cfg argument to build_state 2015-08-24 10:34:40 -07:00
ip_tunnel.c ip_gre: Add support to collect tunnel metadata. 2015-08-10 14:03:54 -07:00
ip_vti.c ip_vti/ip6_vti: Preserve skb->mark after rcv_cb call 2015-05-28 06:23:32 +02:00
ipcomp.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
ipconfig.c net: ipv4: increase dhcp inter device timeout 2015-08-12 16:40:22 -07:00
ipip.c ip_gre: Add support to collect tunnel metadata. 2015-08-10 14:03:54 -07:00
ipmr.c netfilter: Pass socket pointer down through okfn(). 2015-04-07 15:25:55 -04:00
Kconfig tcp: add CDG congestion control 2015-06-11 00:09:12 -07:00
Makefile tcp: add CDG congestion control 2015-06-11 00:09:12 -07:00
netfilter.c netfilter: don't use module_init/exit in core IPV4 code 2015-06-16 14:12:34 -04:00
ping.c ipv6: Nonlocal bind 2015-07-09 21:09:10 -07:00
proc.c net: track success and failure of TCP PMTU probing 2015-07-21 22:36:33 -07:00
protocol.c net: Export inet_offloads and inet6_offloads 2014-09-19 17:15:31 -04:00
raw.c Merge branch 'for-davem' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-13 18:18:05 -04:00
route.c route: move lwtunnel state to dst_entry 2015-08-20 15:42:36 -07:00
syncookies.c tcp: get_cookie_sock() consolidation 2015-06-07 15:19:52 -07:00
sysctl_net_ipv4.c tcp: refine pacing rate determination 2015-08-25 11:33:54 -07:00
tcp_bic.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_cdg.c tcp: do not slow start when cwnd equals ssthresh 2015-07-09 14:22:52 -07:00
tcp_cong.c tcp: do not slow start when cwnd equals ssthresh 2015-07-09 14:22:52 -07:00
tcp_cubic.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_dctcp.c net: tcp: dctcp_update_alpha() fixes. 2015-06-10 23:28:33 -07:00
tcp_diag.c sock_diag: implement a get_info handler for inet 2015-06-15 19:49:22 -07:00
tcp_fastopen.c tcp: Do not call tcp_fastopen_reset_cipher from interrupt context 2015-06-23 02:38:10 -07:00
tcp_highspeed.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_htcp.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_hybla.c tcp: do not slow start when cwnd equals ssthresh 2015-07-09 14:22:52 -07:00
tcp_illinois.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_input.c tcp: refine pacing rate determination 2015-08-25 11:33:54 -07:00
tcp_ipv4.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-08-13 16:23:11 -07:00
tcp_lp.c
tcp_memcontrol.c memcg: cleanup static keys decrement 2015-02-12 18:54:10 -08:00
tcp_metrics.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_minisocks.c inet: inet_twsk_deschedule factorization 2015-07-09 15:12:20 -07:00
tcp_offload.c tcp: reserve tcp_skb_mss() to tcp stack 2015-06-11 16:33:10 -07:00
tcp_output.c tcp: fix slow start after idle vs TSO/GSO 2015-08-25 11:22:50 -07:00
tcp_probe.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_scalable.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_timer.c tcp: do not export tcp_init_xmit_timers() 2015-07-09 21:44:38 -07:00
tcp_vegas.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_vegas.h tcp: prepare CC get_info() access from getsockopt() 2015-04-29 17:10:38 -04:00
tcp_veno.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_westwood.c tcp_westwood: fix tcp_westwood_info() 2015-05-05 19:50:09 -04:00
tcp_yeah.c tcp: stretch ACK fixes prep 2015-01-28 22:18:37 -08:00
tcp.c tcp: fix slow start after idle vs TSO/GSO 2015-08-25 11:22:50 -07:00
tunnel4.c
udp_diag.c sock_diag: specify info_size per inet protocol 2015-06-15 19:49:22 -07:00
udp_impl.h net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
udp_offload.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
udp_tunnel.c net: Modify sk_alloc to not reference count the netns of kernel sockets. 2015-05-11 10:50:18 -04:00
udp.c udp: Handle VRF device in sendmsg 2015-08-13 22:43:20 -07:00
udplite.c
xfrm4_input.c netfilter: Pass socket pointer down through okfn(). 2015-04-07 15:25:55 -04:00
xfrm4_mode_beet.c
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c ipv4: hash net ptr into fragmentation bucket selection 2015-03-25 14:07:04 -04:00
xfrm4_output.c netfilter: Pass socket pointer down through okfn(). 2015-04-07 15:25:55 -04:00
xfrm4_policy.c xfrm: Use VRF master index if output device is enslaved 2015-08-25 11:25:09 -07:00
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c