tcp: Move useless DSACK detection before increasing dupacks
authorSepherosa Ziehau <sephe@dragonflybsd.org>
Fri, 4 May 2012 04:07:14 +0000 (12:07 +0800)
committerSepherosa Ziehau <sephe@dragonflybsd.org>
Fri, 4 May 2012 05:30:22 +0000 (13:30 +0800)
commit12e60b577798d096f760a0fd090e21d6c90dad5d
treeda22dd08c508fcaba21cb3caa06624bde35fff33
parent6d488cc32884ed6ffc6c977f470b8ddcd77cb482
tcp: Move useless DSACK detection before increasing dupacks

- Avoid the spurious retransmit in the following dump:
  http://leaf.dragonflybsd.org/~sephe/fast1.xpl (~9.755sec)
- Loosely meet the requirement of RFC3042: no new segments should be
  sent upon ACKs carrying useless SACK information
- Add sysctl net.inet.tcp.ignore_redun_dsack to disable useless
  DSACK detection; default on
sys/netinet/tcp_input.c