From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: About disabling congestion control
Date: Fri, 07 Jan 2011 11:33:44 +0100
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Cc: Stephen Hemminger <shemminger@vyatta.com>, netdev@vger.kernel.org,
	Michael Kerrisk <mtk.manpages@gmail.com>
To: Syed Obaid Amin <obaidasyed@gmail.com>
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Le vendredi 07 janvier 2011 =C3=A0 05:04 -0500, Syed Obaid Amin a =C3=A9=
crit :
> Thanks for the reply. Yes I also thought to create a sort of NULL
> congestion control type that does nothing. But this way the changes
> would be system wide. BTW, would some one share the insight that why
> linux uses sysctl to select a congestion control algorithm instead of
> socket options.

Hmm, maybe "man 7 tcp" is not up2date.

It mentions TCP_CONGESTION once but doesnt describe it.

CC Michael Kerrisk <mtk.manpages@gmail.com> ;)

http://www.kernel.org/doc/man-pages/online/pages/man7/tcp.7.html


Lets say you have a kernel with support for two congestion controls :

# cat /proc/sys/net/ipv4/tcp_allowed_congestion_control
cubic reno
# cat /proc/sys/net/ipv4/tcp_congestion_control
cubic


Therefore, default is cubic, but you can change to reno if you want.


setsockopt(sock, SOL_TCP, TCP_CONGESTION, "reno", strlen("reno"));