Commit Graph

19 Commits

Author SHA1 Message Date
Yuchung Cheng 9b44190dc1 tcp: refactor F-RTO
The patch series refactor the F-RTO feature (RFC4138/5682).

This is to simplify the loss recovery processing. Existing F-RTO
was developed during the experimental stage (RFC4138) and has
many experimental features.  It takes a separate code path from
the traditional timeout processing by overloading CA_Disorder
instead of using CA_Loss state. This complicates CA_Disorder state
handling because it's also used for handling dubious ACKs and undos.
While the algorithm in the RFC does not change the congestion control,
the implementation intercepts congestion control in various places
(e.g., frto_cwnd in tcp_ack()).

The new code implements newer F-RTO RFC5682 using CA_Loss processing
path.  F-RTO becomes a small extension in the timeout processing
and interfaces with congestion control and Eifel undo modules.
It lets congestion control (module) determines how many to send
independently.  F-RTO only chooses what to send in order to detect
spurious retranmission. If timeout is found spurious it invokes
existing Eifel undo algorithms like DSACK or TCP timestamp based
detection.

The first patch removes all F-RTO code except the sysctl_tcp_frto is
left for the new implementation.  Since CA_EVENT_FRTO is removed, TCP
westwood now computes ssthresh on regular timeout CA_EVENT_LOSS event.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-21 11:47:50 -04:00
Stephen Hemminger a252bebe22 tcp: mark tcp_congestion_ops read_mostly
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-10 00:40:17 -08:00
Eric Dumazet a02cec2155 net: return operator cleanup
Change "return (EXPR);" to "return EXPR;"

return is not a function, parentheses are not required.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-23 14:33:39 -07:00
Stephen Hemminger 30cfd0baf0 [TCP]: congestion control API pass RTT in microseconds
This patch changes the API for the callback that is done after an ACK is
received. It solves a couple of issues:

  * Some congestion controls want higher resolution value of RTT
    (controlled by TCP_CONG_RTT_SAMPLE flag). These don't really want a ktime, but
    all compute a RTT in microseconds.

  * Other congestion control could use RTT at jiffies resolution.

To keep API consistent the units should be the same for both cases, just the
resolution should change.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-31 02:27:57 -07:00
Stephen Hemminger 164891aadf [TCP]: Congestion control API update.
Do some simple changes to make congestion control API faster/cleaner.
* use ktime_t rather than timeval
* merge rtt sampling into existing ack callback
  this means one indirect call versus two per ack.
* use flags bits to store options/settings

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:29:45 -07:00
Thomas Graf 267281058c [TCP] westwood: Use type safe netlink interface
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:27:26 -07:00
Stephen Hemminger 2de979bd7d [TCP]: whitespace cleanup
Add whitespace around keywords.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:24:13 -07:00
YOSHIFUJI Hideaki e905a9edab [NET] IPV4: Fix whitespace errors.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-10 23:19:39 -08:00
Alexey Dobriyan 74975d40b1 [TCP] Congestion control (modulo lp, bic): use BUILD_BUG_ON
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 15:18:13 -07:00
Jörn Engel 6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Luca De Cicco bc726a71d2 [TCP] Westwood: reset RTT min after FRTO
RTT_min is updated each time a timeout event occurs
in order to cope with hard handovers in wireless scenarios such as UMTS.

Signed-off-by: Luca De Cicco <ldecicco@gmail.com>
Signed-off-by: Stephen Hemminger <shemminger@dxpl.pdx.osdl.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:30:38 -07:00
Luca De Cicco b3a92eabe5 [TCP] Westwood: bandwidth filter startup
The bandwidth estimate filter is now initialized with the first
sample in order to have better performances in the case of small
file transfers.

Signed-off-by: Luca De Cicco <ldecicco@gmail.com>
Signed-off-by: Stephen Hemminger <shemminger@dxpl.pdx.osdl.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:30:36 -07:00
Luca De Cicco b7d7a9e3c9 [TCP] Westwood: comment fixes
Cleanup some comments and add more references

Signed-off-by: Luca De Cicco <ldecicco@gmail.com>
Signed-off-by: Stephen Hemminger <shemminger@dxpl.pdx.osdl.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:30:34 -07:00
Stephen Hemminger f61e29018a [TCP] Westwood: fix first sample
Need to update send sequence number tracking after first ack.
Rework of patch from Luca De Cicco.

Signed-off-by: Stephen Hemminger <shemminger@dxpl.pdx.osdl.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:30:32 -07:00
Stephen Hemminger 72dc5b9225 [TCP]: Minimum congestion window consolidation.
Many of the TCP congestion methods all just use ssthresh
as the minimum congestion window on decrease.  Rather than
duplicating the code, just have that be the default if that
handle in the ops structure is not set.

Minor behaviour change to TCP compound.  It probably wants
to use this (ssthresh) as lower bound, rather than ssthresh/2
because the latter causes undershoot on loss.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:29:29 -07:00
Arnaldo Carvalho de Melo a8c2190ee7 [INET_DIAG]: Rename tcp_diag.[ch] to inet_diag.[ch]
Next changeset will introduce net/ipv4/tcp_diag.c, moving the code that was put
transitioanlly in inet_diag.c.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:57:48 -07:00
Arnaldo Carvalho de Melo 73c1f4a033 [TCPDIAG]: Just rename everything to inet_diag
Next changeset will rename tcp_diag.[ch] to inet_diag.[ch].

I'm taking this longer route so as to easy review, making clear the changes
made all along the way.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:57:44 -07:00
Arnaldo Carvalho de Melo 6687e988d9 [ICSK]: Move TCP congestion avoidance members to icsk
This changeset basically moves tcp_sk()->{ca_ops,ca_state,etc} to inet_csk(),
minimal renaming/moving done in this changeset to ease review.

Most of it is just changes of struct tcp_sock * to struct sock * parameters.

With this we move to a state closer to two interesting goals:

1. Generalisation of net/ipv4/tcp_diag.c, becoming inet_diag.c, being used
   for any INET transport protocol that has struct inet_hashinfo and are
   derived from struct inet_connection_sock. Keeps the userspace API, that will
   just not display DCCP sockets, while newer versions of tools can support
   DCCP.

2. INET generic transport pluggable Congestion Avoidance infrastructure, using
   the current TCP CA infrastructure with DCCP.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:56:18 -07:00
Stephen Hemminger 8727076289 [TCP]: Add TCP Westwood congestion control module.
This is the existing 2.6.12 Westwood code moved from tcp_input
to the new congestion framework. A lot of the inline functions
have been eliminated to try and make it clearer.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-06-23 12:24:09 -07:00