linux/net/ipv4
Eric Dumazet 98e09386c0 tcp: tsq: restore minimal amount of queueing
After commit c9eeec26e3 ("tcp: TSQ can use a dynamic limit"), several
users reported throughput regressions, notably on mvneta and wifi
adapters.

802.11 AMPDU requires a fair amount of queueing to be effective.

This patch partially reverts the change done in tcp_write_xmit()
so that the minimal amount is sysctl_tcp_limit_output_bytes.

It also remove the use of this sysctl while building skb stored
in write queue, as TSO autosizing does the right thing anyway.

Users with well behaving NICS and correct qdisc (like sch_fq),
can then lower the default sysctl_tcp_limit_output_bytes value from
128KB to 8KB.

This new usage of sysctl_tcp_limit_output_bytes permits each driver
authors to check how their driver performs when/if the value is set
to a minimum of 4KB.

Normally, line rate for a single TCP flow should be possible,
but some drivers rely on timers to perform TX completion and
too long TX completion delays prevent reaching full throughput.

Fixes: c9eeec26e3 ("tcp: TSQ can use a dynamic limit")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Sujith Manoharan <sujith@msujith.org>
Reported-by: Arnaud Ebalard <arno@natisbad.org>
Tested-by: Sujith Manoharan <sujith@msujith.org>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-14 16:25:14 -05:00
..
netfilter Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nftables 2013-11-04 19:48:57 -05:00
af_inet.c inet: fix a UFO regression 2013-11-08 02:07:59 -05:00
ah4.c ipv4: properly refresh rtable entries on pmtu/redirect events 2013-06-03 00:07:42 -07:00
arp.c net: neighbour: Remove CONFIG_ARPD 2013-09-03 21:41:43 -04:00
cipso_ipv4.c
datagram.c ipv4: Add a socket release callback for datagram sockets 2013-01-21 14:17:05 -05:00
devinet.c net: igmp: Allow user-space configuration of igmp unsolicited report interval 2013-08-09 11:27:46 -07:00
esp4.c net: esp{4,6}: get rid of struct esp_data 2013-10-29 06:39:42 +01:00
fib_frontend.c fib_trie: remove duplicated rcu lock 2013-10-18 13:53:59 -04:00
fib_lookup.h net: ipv4/ipv6: Remove extern from function prototypes 2013-10-19 19:12:11 -04:00
fib_rules.c fib_rules: fix suppressor names and default values 2013-08-03 10:40:23 -07:00
fib_semantics.c fib: Use const struct nl_info * in rtmsg_fib 2013-10-18 14:42:15 -04:00
fib_trie.c fib_trie: only calc for the un-first node 2013-10-10 00:08:07 -04:00
gre_demux.c ipv4: generalize gre_handle_offloads 2013-10-19 19:36:18 -04:00
gre_offload.c ipip: add GSO/TSO support 2013-10-19 19:36:19 -04:00
icmp.c ipv4: processing ancillary IP_TOS or IP_TTL 2013-09-28 15:21:52 -07:00
igmp.c ipv4 igmp: use in_dev_put in timer handlers instead of __in_dev_put 2013-09-30 22:28:56 -07:00
inet_connection_sock.c inet: rename ir_loc_port to ir_num 2013-10-10 14:37:35 -04:00
inet_diag.c inet_diag: use sock_gen_put() 2013-10-17 15:02:02 -04:00
inet_fragment.c inet: remove old fragmentation hash initializing 2013-10-23 17:01:41 -04:00
inet_hashtables.c inet: convert inet_ehash_secret and ipv6_hash_secret to net_get_random_once 2013-10-19 19:45:35 -04:00
inet_lro.c ipv4: replace ip_fast_csum with csum_replace2 2013-03-15 09:12:25 -04:00
inet_timewait_sock.c tcp/dccp: remove twchain 2013-10-08 23:19:24 -04:00
inetpeer.c ip: generate unique IP identificator if local fragmentation is allowed 2013-09-19 14:11:15 -04:00
ip_forward.c ipv4: introduce rt_uses_gateway 2012-10-08 17:42:36 -04:00
ip_fragment.c ipv4: initialize ip4_frags hash secret as late as possible 2013-10-23 17:01:40 -04:00
ip_gre.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-08-16 15:37:26 -07:00
ip_input.c net: add SNMP counters tracking incoming ECN bits 2013-08-08 22:24:59 -07:00
ip_options.c net/ipv4: Ensure that location of timestamp option is stored 2013-03-12 05:35:39 -04:00
ip_output.c ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE 2013-11-05 21:52:27 -05:00
ip_sockglue.c ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE 2013-11-05 21:52:27 -05:00
ip_tunnel.c core/dev: do not ignore dmac in dev_forward_skb() 2013-11-14 02:39:53 -05:00
ip_tunnel_core.c ipv4: generalize gre_handle_offloads 2013-10-19 19:36:18 -04:00
ip_vti.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-10-23 16:49:34 -04:00
ipcomp.c ipv4: properly refresh rtable entries on pmtu/redirect events 2013-06-03 00:07:42 -07:00
ipconfig.c ipconfig: add informative timeout messages while waiting for carrier 2013-04-02 14:35:33 -04:00
ipip.c ipip: add GSO/TSO support 2013-10-19 19:36:19 -04:00
ipmr.c ip: generate unique IP identificator if local fragmentation is allowed 2013-09-19 14:11:15 -04:00
Kconfig net: neighbour: Remove CONFIG_ARPD 2013-09-03 21:41:43 -04:00
Makefile net: gre: move GSO functions to gre_offload 2013-07-03 14:37:39 -07:00
netfilter.c netfilter: add my copyright statements 2013-04-18 20:27:55 +02:00
ping.c net: fix build errors if ipv6 is disabled 2013-10-09 13:04:03 -04:00
proc.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-08-16 15:37:26 -07:00
protocol.c ipv4: Disallow non-namespace aware protocols to register. 2013-02-05 14:42:23 -05:00
raw.c net: ipv4 only populate IP_PKTINFO when needed 2013-10-08 16:27:33 -04:00
route.c ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE 2013-11-05 21:52:27 -05:00
syncookies.c inet: split syncookie keys for ipv4 and ipv6 and initialize with net_get_random_once 2013-10-19 19:45:35 -04:00
sysctl_net_ipv4.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp.c tcp: tsq: restore minimal amount of queueing 2013-11-14 16:25:14 -05:00
tcp_bic.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_cong.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_cubic.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_diag.c
tcp_fastopen.c tcp: enable sockets to use MSG_FASTOPEN by default 2013-11-04 19:57:47 -05:00
tcp_highspeed.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_htcp.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_hybla.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_illinois.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_input.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_ipv4.c ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE 2013-11-05 21:52:27 -05:00
tcp_lp.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_memcontrol.c tcp_memcontrol: Kill struct tcp_memcontrol 2013-10-21 18:43:02 -04:00
tcp_metrics.c tcp: temporarily disable Fast Open on SYN timeout 2013-10-29 22:50:41 -04:00
tcp_minisocks.c ipv6: make lookups simpler and faster 2013-10-09 00:01:25 -04:00
tcp_offload.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-11-04 13:48:30 -05:00
tcp_output.c tcp: tsq: restore minimal amount of queueing 2013-11-14 16:25:14 -05:00
tcp_probe.c ipv6: make lookups simpler and faster 2013-10-09 00:01:25 -04:00
tcp_scalable.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_timer.c tcp: temporarily disable Fast Open on SYN timeout 2013-10-29 22:50:41 -04:00
tcp_vegas.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_vegas.h net: ipv4/ipv6: Remove extern from function prototypes 2013-10-19 19:12:11 -04:00
tcp_veno.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_westwood.c tcp: refactor F-RTO 2013-03-21 11:47:50 -04:00
tcp_yeah.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tunnel4.c
udp.c inet: convert inet_ehash_secret and ipv6_hash_secret to net_get_random_once 2013-10-19 19:45:35 -04:00
udp_diag.c netlink: rename ssk to sk in struct netlink_skb_params 2013-04-19 14:57:56 -04:00
udp_impl.h net: ipv4/ipv6: Remove extern from function prototypes 2013-10-19 19:12:11 -04:00
udp_offload.c ipip: add GSO/TSO support 2013-10-19 19:36:19 -04:00
udplite.c
xfrm4_input.c net: Add skb_unclone() helper function. 2013-02-15 15:10:37 -05:00
xfrm4_mode_beet.c
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2013-09-30 15:24:57 -04:00
xfrm4_output.c xfrm: revert ipv4 mtu determination to dst_mtu 2013-08-26 12:40:53 +02:00
xfrm4_policy.c xfrm: Fix null pointer dereference when decoding sessions 2013-11-01 07:08:46 +01:00
xfrm4_state.c xfrm: make local error reporting more robust 2013-08-14 13:07:12 +02:00
xfrm4_tunnel.c sit: add IPv4 over IPv4 support 2013-05-31 17:19:05 -07:00