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* tcp: whitespace fixesstephen hemminger2014-09-011-1/+0
| | | | | | | | Fix places where there is space before tab, long lines, and awkward if(){, double spacing etc. Add blank line after declaration/initialization. Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: Fix integer-overflows in TCP venoChristoph Paasch2014-07-301-1/+1
| | | | | | | | | | | | | | In veno we do a multiplication of the cwnd and the rtt. This may overflow and thus their result is stored in a u64. However, we first need to cast the cwnd so that actually 64-bit arithmetic is done. A first attempt at fixing 76f1017757aa0 ([TCP]: TCP Veno congestion control) was made by 159131149c2 (tcp: Overflow bug in Vegas), but it failed to add the required cast in tcp_veno_cong_avoid(). Fixes: 76f1017757aa0 ([TCP]: TCP Veno congestion control) Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: remove in_flight parameter from cong_avoid() methodsEric Dumazet2014-05-031-5/+4
| | | | | | | | | | | | Commit e114a710aa505 ("tcp: fix cwnd limited checking to improve congestion control") obsoleted in_flight parameter from tcp_is_cwnd_limited() and its callers. This patch does the removal as promised. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: switch rtt estimations to usec resolutionEric Dumazet2014-02-261-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: properly handle stretch acks in slow startYuchung Cheng2013-11-041-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | Slow start now increases cwnd by 1 if an ACK acknowledges some packets, regardless the number of packets. Consequently slow start performance is highly dependent on the degree of the stretch ACKs caused by receiver or network ACK compression mechanisms (e.g., delayed-ACK, GRO, etc). But slow start algorithm is to send twice the amount of packets of packets left so it should process a stretch ACK of degree N as if N ACKs of degree 1, then exits when cwnd exceeds ssthresh. A follow up patch will use the remainder of the N (if greater than 1) to adjust cwnd in the congestion avoidance phase. In addition this patch retires the experimental limited slow start (LSS) feature. LSS has multiple drawbacks but questionable benefit. The fractional cwnd increase in LSS requires a loop in slow start even though it's rarely used. Configuring such an increase step via a global sysctl on different BDPS seems hard. Finally and most importantly the slow start overshoot concern is now better covered by the Hybrid slow start (hystart) enabled by default. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: mark tcp_congestion_ops read_mostlyStephen Hemminger2011-03-101-1/+1
| | | | | Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Update broken web addresses in the kernel.Justin P. Mattock2010-10-181-1/+1
| | | | | | | | | | | | | | | | | The patch below updates broken web addresses in the kernel Signed-off-by: Justin P. Mattock <justinmattock@gmail.com> Cc: Maciej W. Rozycki <macro@linux-mips.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Finn Thain <fthain@telegraphics.com.au> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Matt Turner <mattst88@gmail.com> Cc: Dimitry Torokhov <dmitry.torokhov@gmail.com> Cc: Mike Frysinger <vapier.adi@gmail.com> Acked-by: Ben Pfaff <blp@cs.stanford.edu> Acked-by: Hans J. Koch <hjk@linutronix.de> Reviewed-by: Finn Thain <fthain@telegraphics.com.au> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* net/ipv4: Move && and || to end of previous lineJoe Perches2009-11-231-3/+2
| | | | | | | | | | | | | | | | | | On Sun, 2009-11-22 at 16:31 -0800, David Miller wrote: > It should be of the form: > if (x && > y) > > or: > if (x && y) > > Fix patches, rather than complaints, for existing cases where things > do not follow this pattern are certainly welcome. Also collapsed some multiple tabs to single space. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: add helper for AI algorithmIlpo Järvinen2009-03-021-6/+1
| | | | | | | | | | | | | | | | | | | | It seems that implementation in yeah was inconsistent to what other did as it would increase cwnd one ack earlier than the others do. Size benefits: bictcp_cong_avoid | -36 tcp_cong_avoid_ai | +52 bictcp_cong_avoid | -34 tcp_scalable_cong_avoid | -36 tcp_veno_cong_avoid | -12 tcp_yeah_cong_avoid | -38 = -104 bytes total Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: fix returning void-valued expression warningsHarvey Harrison2008-05-011-2/+4
| | | | | | | | | | | | | | 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 Andrew2008-04-301-3/+5
| | | | | | | | | | | | | 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 Järvinen2008-01-281-4/+3
| | | | | | 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]: congestion control API pass RTT in microsecondsStephen Hemminger2007-07-311-3/+3
| | | | | | | | | | | | | | | | | 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 Hemminger2007-07-181-3/+3
| | | | | | | | | 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 Järvinen2007-06-151-0/+3
| | | | | | | | | | | | | | 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 Hideaki2007-04-251-1/+1
| | | | | | | 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]: Congestion control API update.Stephen Hemminger2007-04-251-3/+7
| | | | | | | | | | | 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] Congestion control (modulo lp, bic): use BUILD_BUG_ONAlexey Dobriyan2006-09-221-1/+1
| | | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Remove unnecessary config.h includes from net/Dave Jones2006-09-221-1/+0
| | | | | | | config.h is automatically included by kbuild these days. Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Minimum congestion window consolidation.Stephen Hemminger2006-06-171-7/+0
| | | | | | | | | | | | | | 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>
* [TCP]: TCP Veno congestion controlBin Zhou2006-06-171-0/+238
TCP Veno module is a new congestion control module to improve TCP performance over wireless networks. The key innovation in TCP Veno is the enhancement of TCP Reno/Sack congestion control algorithm by using the estimated state of a connection based on TCP Vegas. This scheme significantly reduces "blind" reduction of TCP window regardless of the cause of packet loss. This work is based on the research paper "TCP Veno: TCP Enhancement for Transmission over Wireless Access Networks." C. P. Fu, S. C. Liew, IEEE Journal on Selected Areas in Communication, Feb. 2003. Original paper and many latest research works on veno: http://www.ntu.edu.sg/home/ascpfu/veno/veno.html Signed-off-by: Bin Zhou <zhou0022@ntu.edu.sg> Cheng Peng Fu <ascpfu@ntu.edu.sg> Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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