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Diffstat (limited to 'share/man/man7/tuning.7')
-rw-r--r-- | share/man/man7/tuning.7 | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/share/man/man7/tuning.7 b/share/man/man7/tuning.7 index daa93d3..4a18e25 100644 --- a/share/man/man7/tuning.7 +++ b/share/man/man7/tuning.7 @@ -522,6 +522,29 @@ In such environments, setting the sysctl to 0 may reduce the occurrence of TCP session disconnections. .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 effects data transmission (uploading / server-side). It does not +effect data reception (downloading). +.Pp +The .Va kern.ipc.somaxconn sysctl limits the size of the listen queue for accepting new TCP connections. The default value of 128 is typically too low for robust handling of new |