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  1. 22 9月, 2015 1 次提交
    • Y
      tcp: usec resolution SYN/ACK RTT · 0f1c28ae
      由 Yuchung Cheng 提交于 
      Currently SYN/ACK RTT is measured in jiffies. For LAN the SYN/ACK
RTT is often measured as 0ms or sometimes 1ms, which would affect
RTT estimation and min RTT samping used by some congestion control.

This patch improves SYN/ACK RTT to be usec resolution if platform
supports it. While the timestamping of SYN/ACK is done in request
sock, the RTT measurement is carefully arranged to avoid storing
another u64 timestamp in tcp_sock.

For regular handshake w/o SYNACK retransmission, the RTT is sampled
right after the child socket is created and right before the request
sock is released (tcp_check_req() in tcp_minisocks.c)

For Fast Open the child socket is already created when SYN/ACK was
sent, the RTT is sampled in tcp_rcv_state_process() after processing
the final ACK an right before the request socket is released.

If the SYN/ACK was retransmistted or SYN-cookie was used, we rely
on TCP timestamps to measure the RTT. The sample is taken at the
same place in tcp_rcv_state_process() after the timestamp values
are validated in tcp_validate_incoming(). Note that we do not store
TS echo value in request_sock for SYN-cookies, because the value
is already stored in tp->rx_opt used by tcp_ack_update_rtt().

One side benefit is that the RTT measurement now happens before
initializing congestion control (of the passive side). Therefore
the congestion control can use the SYN/ACK RTT.
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      0f1c28ae
  3. 18 9月, 2015 19 次提交
  5. 16 9月, 2015 4 次提交
  7. 11 9月, 2015 2 次提交
    • E
      tcp_cubic: better follow cubic curve after idle period · 30927520
      由 Eric Dumazet 提交于 
      Jana Iyengar found an interesting issue on CUBIC :

The epoch is only updated/reset initially and when experiencing losses.
The delta "t" of now - epoch_start can be arbitrary large after app idle
as well as the bic_target. Consequentially the slope (inverse of
ca->cnt) would be really large, and eventually ca->cnt would be
lower-bounded in the end to 2 to have delayed-ACK slow-start behavior.

This particularly shows up when slow_start_after_idle is disabled
as a dangerous cwnd inflation (1.5 x RTT) after few seconds of idle
time.

Jana initial fix was to reset epoch_start if app limited,
but Neal pointed out it would ask the CUBIC algorithm to recalculate the
curve so that we again start growing steeply upward from where cwnd is
now (as CUBIC does just after a loss). Ideally we'd want the cwnd growth
curve to be the same shape, just shifted later in time by the amount of
the idle period.
Reported-by: NJana Iyengar <jri@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Sangtae Ha <sangtae.ha@gmail.com>
Cc: Lawrence Brakmo <lawrence@brakmo.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      30927520
    • N
      tcp: generate CA_EVENT_TX_START on data frames · 05c5a46d
      由 Neal Cardwell 提交于 
      Issuing a CC TX_START event on control frames like pure ACK
is a waste of time, as a CC should not care.

Following patch needs this change, as we want CUBIC to properly track
idle time at a low cost, with a single TX_START being generated.

Yuchung might slightly refine the condition triggering TX_START
on a followup patch.
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Cc: Jana Iyengar <jri@google.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Sangtae Ha <sangtae.ha@gmail.com>
Cc: Lawrence Brakmo <lawrence@brakmo.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      05c5a46d
  9. 10 9月, 2015 1 次提交
    • P
      net: ipv6: use common fib_default_rule_pref · f53de1e9
      由 Phil Sutter 提交于 
      This switches IPv6 policy routing to use the shared
fib_default_rule_pref() function of IPv4 and DECnet. It is also used in
multicast routing for IPv4 as well as IPv6.

The motivation for this patch is a complaint about iproute2 behaving
inconsistent between IPv4 and IPv6 when adding policy rules: Formerly,
IPv6 rules were assigned a fixed priority of 0x3FFF whereas for IPv4 the
assigned priority value was decreased with each rule added.

Since then all users of the default_pref field have been converted to
assign the generic function fib_default_rule_pref(), fib_nl_newrule()
may just use it directly instead. Therefore get rid of the function
pointer altogether and make fib_default_rule_pref() static, as it's not
used outside fib_rules.c anymore.
Signed-off-by: NPhil Sutter <phil@nwl.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      f53de1e9
  11. 03 9月, 2015 1 次提交
    • D
      netfilter: nf_dup{4, 6}: fix build error when nf_conntrack disabled · a82b0e63
      由 Daniel Borkmann 提交于 
      While testing various Kconfig options on another issue, I found that
the following one triggers as well on allmodconfig and nf_conntrack
disabled:

  net/ipv4/netfilter/nf_dup_ipv4.c: In function ‘nf_dup_ipv4’:
  net/ipv4/netfilter/nf_dup_ipv4.c:72:20: error: ‘nf_skb_duplicated’ undeclared (first use in this function)
    if (this_cpu_read(nf_skb_duplicated))
  [...]
  net/ipv6/netfilter/nf_dup_ipv6.c: In function ‘nf_dup_ipv6’:
  net/ipv6/netfilter/nf_dup_ipv6.c:66:20: error: ‘nf_skb_duplicated’ undeclared (first use in this function)
    if (this_cpu_read(nf_skb_duplicated))

Fix it by including directly the header where it is defined.

Fixes: bbde9fc1 ("netfilter: factor out packet duplication for IPv4/IPv6")
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a82b0e63
  13. 02 9月, 2015 1 次提交
  15. 01 9月, 2015 5 次提交
  17. 31 8月, 2015 2 次提交
  19. 30 8月, 2015 4 次提交