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| author |   Yuchung Cheng <ycheng@google.com> | 2017-01-12 22:11:39 -0800 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2017-01-13 22:37:16 -0500 |
| commit | bec41a11dd3dc8c54f766b4f494140ca92ba7c10 (patch) | |
| tree | 62a888654cc55636c2ab85adf331db2361aae118 /Documentation | |
| parent | tcp: remove forward retransmit feature (diff) | |
| download | linux-dev-bec41a11dd3dc8c54f766b4f494140ca92ba7c10.tar.xz linux-dev-bec41a11dd3dc8c54f766b4f494140ca92ba7c10.zip | |
tcp: remove early retransmit
This patch removes the support of RFC5827 early retransmit (i.e.,
fast recovery on small inflight with <3 dupacks) because it is
subsumed by the new RACK loss detection. More specifically when
RACK receives DUPACKs, it'll arm a reordering timer to start fast
recovery after a quarter of (min)RTT, hence it covers the early
retransmit except RACK does not limit itself to specific inflight
or dupack numbers.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 19 |
1 files changed, 5 insertions, 14 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 7dd65c9cf707..7de2cf79e16f 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -246,21 +246,12 @@ tcp_dsack - BOOLEAN Allows TCP to send "duplicate" SACKs. tcp_early_retrans - INTEGER - Enable Early Retransmit (ER), per RFC 5827. ER lowers the threshold - for triggering fast retransmit when the amount of outstanding data is - small and when no previously unsent data can be transmitted (such - that limited transmit could be used). Also controls the use of - Tail loss probe (TLP) that converts RTOs occurring due to tail - losses into fast recovery (draft-dukkipati-tcpm-tcp-loss-probe-01). + Tail loss probe (TLP) converts RTOs occurring due to tail + losses into fast recovery (draft-ietf-tcpm-rack). Note that + TLP requires RACK to function properly (see tcp_recovery below) Possible values: - 0 disables ER - 1 enables ER - 2 enables ER but delays fast recovery and fast retransmit - by a fourth of RTT. This mitigates connection falsely - recovers when network has a small degree of reordering - (less than 3 packets). - 3 enables delayed ER and TLP. - 4 enables TLP only. + 0 disables TLP + 3 or 4 enables TLP Default: 3 tcp_ecn - INTEGER |