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* tcp: tcp_vegas cong avoid fix Doug Leith2008-12-09
| | | | | | | | | | | | | | | | | | | | | | | | | This patch addresses a book-keeping issue in tcp_vegas.c. At present tcp_vegas does separate book-keeping of cwnd based on packet sequence numbers. A mismatch can develop between this book-keeping and tp->snd_cwnd due, for example, to delayed acks acking multiple packets. When vegas transitions to reno operation (e.g. following loss), then this mismatch leads to incorrect behaviour (akin to a cwnd backoff). This seems mostly to affect operation at low cwnds where delayed acking can lead to a significant fraction of cwnd being covered by a single ack, leading to the book-keeping mismatch. This patch modifies the congestion avoidance update to avoid the need for separate book-keeping while leaving vegas congestion avoidance functionally unchanged. A secondary advantage of this modification is that the use of fixed-point (via V_PARAM_SHIFT) and 64 bit arithmetic is no longer necessary, simplifying the code. Some example test measurements with the patched code (confirming no functional change in the congestion avoidance algorithm) can be seen at: http://www.hamilton.ie/doug/vegaspatch/ Signed-off-by: Doug Leith <doug.leith@nuim.ie> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: tcp_vegas ssthresh bug fixDoug Leith2008-12-04
| | | | | | | | | | | | | | This patch fixes a bug in tcp_vegas.c. At the moment this code leaves ssthresh untouched. However, this means that the vegas congestion control algorithm is effectively unable to reduce cwnd below the ssthresh value (if the vegas update lowers the cwnd below ssthresh, then slow start is activated to raise it back up). One example where this matters is when during slow start cwnd overshoots the link capacity and a flow then exits slow start with ssthresh set to a value above where congestion avoidance would like to adjust it. Signed-off-by: Doug Leith <doug.leith@nuim.ie> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: fix returning void-valued expression warningsHarvey Harrison2008-05-01
| | | | | | | | | | | | | | drivers/net/8390.c:37:2: warning: returning void-valued expression drivers/net/bnx2.c:1635:3: warning: returning void-valued expression drivers/net/xen-netfront.c:1806:2: warning: returning void-valued expression net/ipv4/tcp_hybla.c:105:3: warning: returning void-valued expression net/ipv4/tcp_vegas.c:171:3: warning: returning void-valued expression net/ipv4/tcp_veno.c:123:3: warning: returning void-valued expression net/sysctl_net.c:85:2: warning: returning void-valued expression Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: Overflow bug in VegasLachlan Andrew2008-04-30
| | | | | | | | | | | | | From: Lachlan Andrew <lachlan.andrew@gmail.com> There is an overflow bug in net/ipv4/tcp_vegas.c for large BDPs (e.g. 400Mbit/s, 400ms). The multiplication (old_wnd * vegas->baseRTT) << V_PARAM_SHIFT overflows a u32. [ Fix tcp_veno.c too, it has similar calculations. -DaveM ] Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Cong.ctrl modules: remove unused good_ack from cong_avoidIlpo Järvinen2008-01-28
| | | | | | Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] vegas: Fix a bug in disabling slow start by gamma parameter.Xiaoliang (David) Wei2007-10-30
| | | | | | | | | | | | | TCP Vegas implementation has a bug in the process of disabling slow-start with gamma parameter. The bug may lead to extreme unfairness in the presence of early packet loss. See details in: http://www.cs.caltech.edu/~weixl/technical/ns2linux/known_linux/index.html#vegas Switch the order of "if (tp->snd_cwnd <= tp->snd_ssthresh)" statement and "if (diff > gamma)" statement to eliminate the problem. Signed-off-by: Xiaoliang (David) Wei <davidwei79@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: congestion control API pass RTT in microsecondsStephen Hemminger2007-07-31
| | | | | | | | | | | | | | | | | 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>
* [TCP]: remove unused argument to cong_avoid opStephen Hemminger2007-07-18
| | | | | | | | | None of the existing TCP congestion controls use the rtt value pased in the ca_ops->cong_avoid interface. Which is lucky because seq_rtt could have been -1 when handling a duplicate ack. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Congestion control API RTT sampling fixIlpo Järvinen2007-06-15
| | | | | | | | | | | | | | Commit 164891aadf1721fca4dce473bb0e0998181537c6 broke RTT sampling of congestion control modules. Inaccurate timestamps could be fed to them without providing any way for them to identify such cases. Previously RTT sampler was called only if FLAG_RETRANS_DATA_ACKED was not set filtering inaccurate timestamps nicely. In addition, the new behavior could give an invalid timestamp (zero) to RTT sampler if only skbs with TCPCB_RETRANS were ACKed. This solves both problems. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Fix linkage errors on i386.YOSHIFUJI Hideaki2007-04-26
| | | | | | | To avoid raw division, use ktime_to_timeval() to get usec. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] TCP YEAH: Use vegas dont copy it.Stephen Hemminger2007-04-26
| | | | | | | | Rather than using a copy of vegas code, the YEAH code should just have it exported so there is common code. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Congestion control API update.Stephen Hemminger2007-04-26
| | | | | | | | | | | 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>
* [TCP] vegas: Use type safe netlink interfaceThomas Graf2007-04-26
| | | | | Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET] IPV4: Fix whitespace errors.YOSHIFUJI Hideaki2007-02-11
| | | | | Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] Vegas: Increase default alpha to 2 and beta to 4.David S. Miller2006-12-03
| | | | | | | | | This helps Vegas cope better with delayed ACKs, see analysis at: http://www.cs.caltech.edu/%7Eweixl/technical/ns2linux/known_linux/index.html#vegas Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] Congestion control (modulo lp, bic): use BUILD_BUG_ONAlexey Dobriyan2006-09-22
| | | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-30
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [TCP] tcp_vegas: Fix slow startThomas Young2006-01-04
| | | | | | | | Vegas' slow start was only adding one MSS per RTT rather than one for every ack. Slow start behavior should now match Reno. Signed-off-by: Thomas Young <tyo@ee.mu.oz.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] Vegas: Remove extra call to tcp_vegas_rtt_calcThomas Young2005-12-06
| | | | | | | | | Remove unneeded call to tcp_vegas_rtt_calc. The more accurate microsecond value has already been registered prior to calling tcp_vegas_cong_avoid. Signed-off-by: Thomas Young <tyo@ee.mu.oz.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] Vegas: stop resetting rtt every ackThomas Young2005-12-06
| | | | | | | | Move the resetting of rtt measurements to inside the once per RTT block of code. Signed-off-by: Thomas Young <tyo@ee.mu.oz.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] TCP: fix vegas buildJeff Garzik2005-11-11
| | | | | | | Recent TCP changes broke the build. Signed-off-by: Jeff Garzik <jgarzik@pobox.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [TCP]: add tcp_slow_start helperStephen Hemminger2005-11-10
| | | | | | | | Move all the code that does linear TCP slowstart to one inline function to ease later patch to add ABC support. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [INET_DIAG]: Rename tcp_diag.[ch] to inet_diag.[ch]Arnaldo Carvalho de Melo2005-08-29
| | | | | | | | 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>
* [TCPDIAG]: Just rename everything to inet_diagArnaldo Carvalho de Melo2005-08-29
| | | | | | | | | | 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>
* [ICSK]: Move TCP congestion avoidance members to icskArnaldo Carvalho de Melo2005-08-29
| | | | | | | | | | | | | | | | | | | | | 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>
* [TCP]: Add TCP Vegas congestion control module.Stephen Hemminger2005-06-23
TCP Vegas code modified for the new TCP infrastructure. Vegas now uses microsecond resolution timestamps for better estimation of performance over higher speed links. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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