[TCP]: Document several sysctls.
This adds documentation for tcp_moderate_rcvbuf, tcp_no_metrics_save,
tcp_base_mss, and tcp_mtu_probing.
Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index a0f6842..d3aae1f 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -147,6 +147,11 @@
More congestion control algorithms may be available as modules,
but not loaded.
+tcp_base_mss - INTEGER
+ The initial value of search_low to be used by Packetization Layer
+ Path MTU Discovery (MTU probing). If MTU probing is enabled,
+ this is the inital MSS used by the connection.
+
tcp_congestion_control - STRING
Set the congestion control algorithm to be used for new
connections. The algorithm "reno" is always available, but
@@ -243,6 +248,27 @@
Defaults are calculated at boot time from amount of available
memory.
+tcp_moderate_rcvbuf - BOOLEAN
+ If set, TCP performs receive buffer autotuning, attempting to
+ automatically size the buffer (no greater than tcp_rmem[2]) to
+ match the size required by the path for full throughput. Enabled by
+ default.
+
+tcp_mtu_probing - INTEGER
+ Controls TCP Packetization-Layer Path MTU Discovery. Takes three
+ values:
+ 0 - Disabled
+ 1 - Disabled by default, enabled when an ICMP black hole detected
+ 2 - Always enabled, use initial MSS of tcp_base_mss.
+
+tcp_no_metrics_save - BOOLEAN
+ By default, TCP saves various connection metrics in the route cache
+ when the connection closes, so that connections established in the
+ near future can use these to set initial conditions. Usually, this
+ increases overall performance, but may sometimes cause performance
+ degredation. If set, TCP will not cache metrics on closing
+ connections.
+
tcp_orphan_retries - INTEGER
How may times to retry before killing TCP connection, closed
by our side. Default value 7 corresponds to ~50sec-16min