Eric Lee / smarc-fsl-linux-kernel

10 Jul, 2015

1 commit

  • 76174004a   tcp: do not slow start when cwnd equals ssthresh ... Browse Code »

    In the original design slow start is only used to raise cwnd
    when cwnd is stricly below ssthresh. It makes little sense
    to slow start when cwnd == ssthresh: especially
    when hystart has set ssthresh in the initial ramp, or after
    recovery when cwnd resets to ssthresh. Not doing so will
    also help reduce the buffer bloat slightly.

    Signed-off-by: Yuchung Cheng
    Signed-off-by: Neal Cardwell
    Signed-off-by: Eric Dumazet
    Signed-off-by: Nandita Dukkipati
    Signed-off-by: David S. Miller

    Yuchung Cheng
     

02 Sep, 2014

1 commit

  • 688d1945b   tcp: whitespace fixes ... Browse Code »

    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
    Signed-off-by: David S. Miller

    stephen hemminger
     

04 May, 2014

1 commit

27 Feb, 2014

1 commit

  • 740b0f184   tcp: switch rtt estimations to usec resolution ... Browse Code »

    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
    Acked-by: Neal Cardwell
    Cc: Stephen Hemminger
    Cc: Yuchung Cheng
    Cc: Larry Brakmo
    Cc: Julian Anastasov
    Signed-off-by: David S. Miller

    Eric Dumazet
     

14 Feb, 2014

1 commit

05 Nov, 2013

1 commit

  • 9f9843a75   tcp: properly handle stretch acks in slow start ... Browse Code »

    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
    Signed-off-by: Neal Cardwell
    Signed-off-by: Eric Dumazet
    Signed-off-by: David S. Miller

    Yuchung Cheng
     

18 May, 2012

1 commit

10 Mar, 2011

1 commit

02 Jun, 2010

1 commit

08 Oct, 2008

1 commit

01 May, 2008

1 commit

  • ab59859de   net: fix returning void-valued expression warnings ... Browse Code »

    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
    Acked-by: Alan Cox
    Signed-off-by: David S. Miller

    Harvey Harrison
     

29 Jan, 2008

1 commit

18 Jul, 2007

1 commit

26 Apr, 2007

1 commit

23 Sep, 2006

1 commit

01 Jul, 2006

1 commit

11 Nov, 2005

1 commit

  • f4805eded   [TCP]: fix congestion window update when using TSO deferal ... Browse Code »

    TCP peformance with TSO over networks with delay is awful.
    On a 100Mbit link with 150ms delay, we get 4Mbits/sec with TSO and
    50Mbits/sec without TSO.

    The problem is with TSO, we intentionally do not keep the maximum
    number of packets in flight to fill the window, we hold out to until
    we can send a MSS chunk. But, we also don't update the congestion window
    unless we have filled, as per RFC2861.

    This patch replaces the check for the congestion window being full
    with something smarter that accounts for TSO.

    Signed-off-by: Stephen Hemminger
    Signed-off-by: David S. Miller

    Stephen Hemminger
     

30 Aug, 2005

1 commit

  • 6687e988d   [ICSK]: Move TCP congestion avoidance members to icsk ... Browse Code »

    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
    Signed-off-by: David S. Miller

    Arnaldo Carvalho de Melo
     

24 Jun, 2005

1 commit

  • 835b3f0c0   [TCP]: Add TCP Hybla congestion control module. ... Browse Code »

    TCP Hybla congestion avoidance.

    - "In heterogeneous networks, TCP connections that incorporate a
    terrestrial or satellite radio link are greatly disadvantaged with
    respect to entirely wired connections, because of their longer round
    trip times (RTTs). To cope with this problem, a new TCP proposal, the
    TCP Hybla, is presented and discussed in the paper[1]. It stems from an
    analytical evaluation of the congestion window dynamics in the TCP
    standard versions (Tahoe, Reno, NewReno), which suggests the necessary
    modifications to remove the performance dependence on RTT.[...]"[1]

    [1]: Carlo Caini, Rosario Firrincieli, "TCP Hybla: a TCP enhancement for
    heterogeneous networks",
    International Journal of Satellite Communications and Networking
    Volume 22, Issue 5 , Pages 547 - 566. September 2004.

    Signed-off-by: Daniele Lacamera (root at danielinux.net)net
    Signed-off-by: Stephen Hemminger
    Signed-off-by: David S. Miller

    Daniele Lacamera