git: tcp: Set upper limit for the DupThresh generated by the NCR

[Sepherosa Ziehau]

commit dab842be9e4b6b67ea23800303234aae9de63dd1
Author: Sepherosa Ziehau <sephe at dragonflybsd.org>
Date:   Fri Jul 18 20:00:24 2014 +0800

    tcp: Set upper limit for the DupThresh generated by the NCR
    
    The DupThresh could be pretty large due to large amount of outstanding
    segments on the fast local area network.  If the reception side really
    lost some segments, the fast recovery would be delayed for a long time.
    It would become even worse, if the reception side aggregated ACKs, i.e.
    widely used LRO; it could even cause timeout retransmition, which is
    highly unappreciated on the fast local area network.  Put an upper
    limit for the DupThresh, currently 16, so that fast recovery could take
    over segment retransmittion in a timely fashion.  The upper limit of
    DupThresh could be controlled by sysctl net.inet.tcp.ncr_rxtthresh_max.

Summary of changes:
 sys/netinet/tcp_input.c | 3 ++-
 sys/netinet/tcp_subr.c  | 5 +++++
 sys/netinet/tcp_var.h   | 1 +
 3 files changed, 8 insertions(+), 1 deletion(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/dab842be9e4b6b67ea23800303234aae9de63dd1


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