diff --git a/share/man/man7/tuning.7 b/share/man/man7/tuning.7 index 36544bbef7f7..5e228dd907d9 100644 --- a/share/man/man7/tuning.7 +++ b/share/man/man7/tuning.7 @@ -23,7 +23,7 @@ .\" .\" $FreeBSD$ .\" -.Dd October 20, 2012 +.Dd December 8, 2012 .Dt TUNING 7 .Os .Sh NAME @@ -459,52 +459,6 @@ the sysctl rather than disable delayed acks. .Pp The -.Va net.inet.tcp.inflight.enable -sysctl turns on bandwidth delay product limiting for all TCP connections. -The system will attempt to calculate the bandwidth delay product for each -connection and limit the amount of data queued to the network to just the -amount required to maintain optimum throughput. -This feature is useful -if you are serving data over modems, GigE, or high speed WAN links (or -any other link with a high bandwidth*delay product), especially if you are -also using window scaling or have configured a large send window. -If you enable this option, you should also be sure to set -.Va net.inet.tcp.inflight.debug -to 0 (disable debugging), and for production use setting -.Va net.inet.tcp.inflight.min -to at least 6144 may be beneficial. -Note however, that setting high -minimums may effectively disable bandwidth limiting depending on the link. -The limiting feature reduces the amount of data built up in intermediate -router and switch packet queues as well as reduces the amount of data built -up in the local host's interface queue. -With fewer packets queued up, -interactive connections, especially over slow modems, will also be able -to operate with lower round trip times. -However, note that this feature -only affects data transmission (uploading / server-side). -It does not -affect data reception (downloading). -.Pp -Adjusting -.Va net.inet.tcp.inflight.stab -is not recommended. -This parameter defaults to 20, representing 2 maximal packets added -to the bandwidth delay product window calculation. -The additional -window is required to stabilize the algorithm and improve responsiveness -to changing conditions, but it can also result in higher ping times -over slow links (though still much lower than you would get without -the inflight algorithm). -In such cases you may -wish to try reducing this parameter to 15, 10, or 5, and you may also -have to reduce -.Va net.inet.tcp.inflight.min -(for example, to 3500) to get the desired effect. -Reducing these parameters -should be done as a last resort only. -.Pp -The .Va net.inet.ip.portrange.* sysctls control the port number ranges automatically bound to TCP and UDP sockets.