TCP inflight limiter disabled and scheduled for removal

[Steven Hartland]

Will be glad to see this go, only ever caused performance issues here :(

    Regards
    Steve

----- Original Message ----- 
From: "Andre Oppermann" <andre at freebsd.org>
To: <freebsd-net at freebsd.org>
Sent: Sunday, August 15, 2010 2:29 PM
Subject: TCP inflight limiter disabled and scheduled for removal


> FYI the TCP inflight limiter is now disabled by default and will be
> removed soon.  It was interfering with the congestion control algorithms
> and the upcoming pluggable congestion control framework allows other
> approaches to be selected at runtime.
> 
> -------- Original Message --------
> Subject: svn commit: r211315 - head/sys/netinet
> Date: Sat, 14 Aug 2010 20:40:55 +0000 (UTC)
> From: Andre Oppermann <andre at FreeBSD.org>
> To: src-committers at freebsd.org, svn-src-all at freebsd.org,        svn-src-head at freebsd.org
> 
> Author: andre
> Date: Sat Aug 14 20:40:55 2010
> New Revision: 211315
> URL: http://svn.freebsd.org/changeset/base/211315
> 
> Log:
>   Disable TCP inflight limiter by default.
> 
>   It was experimental and interferes with the normal congestion control
>   algorithms by instating a separate, possibly lower, ceiling for the
>   amount of data that is in flight to the remote host.  With high speed
>   internet connections the inflight limit frequently has been estimated
>   too low due to the noisy nature of the RTT measurements.
> 
>   This code gives way for the upcoming pluggable congestion control
>   framework.  It is the task of the congestion control algorithm to
>   set the congestion window and amount of inflight data without external
>   interference.
> 
>   Reviewed by: lstewart
>   MFC after: 1 week
>   Removal after: 1 month
> 
> Modified:
>   head/sys/netinet/tcp_subr.c
> 
> Modified: head/sys/netinet/tcp_subr.c
> ==============================================================================
> --- head/sys/netinet/tcp_subr.c Sat Aug 14 20:12:10 2010 (r211314)
> +++ head/sys/netinet/tcp_subr.c Sat Aug 14 20:40:55 2010 (r211315)
> @@ -221,7 +221,7 @@ SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO,
>  SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0,
>      "TCP inflight data limiting");
> 
> -static VNET_DEFINE(int, tcp_inflight_enable) = 1;
> +static VNET_DEFINE(int, tcp_inflight_enable) = 0;
>  #define V_tcp_inflight_enable VNET(tcp_inflight_enable)
>  SYSCTL_VNET_INT(_net_inet_tcp_inflight, OID_AUTO, enable, CTLFLAG_RW,
>      &VNET_NAME(tcp_inflight_enable), 0,
> 
> 
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