Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild

[firefly-linux-kernel-4.4.55.git] / Documentation / networking / ip-sysctl.txt

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 32c2e9da5f3a3dd0f2c522799ffa92575f64a01e..17a6e46fbd43abfce8ad5558f99200f8389ac650 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -180,13 +180,20 @@ tcp_fin_timeout - INTEGER
        to live longer. Cf. tcp_max_orphans.
 
 tcp_frto - INTEGER
        to live longer. Cf. tcp_max_orphans.
 
 tcp_frto - INTEGER

-       Enables F-RTO, an enhanced recovery algorithm for TCP retransmission
+       Enables Forward RTO-Recovery (F-RTO) defined in RFC4138.
+       F-RTO is an enhanced recovery algorithm for TCP retransmission

        timeouts.  It is particularly beneficial in wireless environments
        where packet loss is typically due to random radio interference
        timeouts.  It is particularly beneficial in wireless environments
        where packet loss is typically due to random radio interference

-       rather than intermediate router congestion. If set to 1, basic
-       version is enabled. 2 enables SACK enhanced F-RTO, which is
-       EXPERIMENTAL. The basic version can be used also when SACK is
-       enabled for a flow through tcp_sack sysctl.
+       rather than intermediate router congestion.  F-RTO is sender-side
+       only modification.  Therefore it does not require any support from
+       the peer, but in a typical case, however, where wireless link is
+       the local access link and most of the data flows downlink, the
+       faraway servers should have F-RTO enabled to take advantage of it.
+       If set to 1, basic version is enabled.  2 enables SACK enhanced
+       F-RTO if flow uses SACK.  The basic version can be used also when
+       SACK is in use though scenario(s) with it exists where F-RTO
+       interacts badly with the packet counting of the SACK enabled TCP
+       flow.

 
 tcp_frto_response - INTEGER
        When F-RTO has detected that a TCP retransmission timeout was
 
 tcp_frto_response - INTEGER
        When F-RTO has detected that a TCP retransmission timeout was


@@ -286,7 +293,7 @@ tcp_no_metrics_save - BOOLEAN
        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
        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
+       degradation.  If set, TCP will not cache metrics on closing

        connections.
 
 tcp_orphan_retries - INTEGER
        connections.
 
 tcp_orphan_retries - INTEGER


@@ -439,6 +446,33 @@ tcp_dma_copybreak - INTEGER
        and CONFIG_NET_DMA is enabled.
        Default: 4096
 
        and CONFIG_NET_DMA is enabled.
        Default: 4096
 

+UDP variables:
+
+udp_mem - vector of 3 INTEGERs: min, pressure, max
+       Number of pages allowed for queueing by all UDP sockets.
+
+       min: Below this number of pages UDP is not bothered about its
+       memory appetite. When amount of memory allocated by UDP exceeds
+       this number, UDP starts to moderate memory usage.
+
+       pressure: This value was introduced to follow format of tcp_mem.
+
+       max: Number of pages allowed for queueing by all UDP sockets.
+
+       Default is calculated at boot time from amount of available memory.
+
+udp_rmem_min - INTEGER
+       Minimal size of receive buffer used by UDP sockets in moderation.
+       Each UDP socket is able to use the size for receiving data, even if
+       total pages of UDP sockets exceed udp_mem pressure. The unit is byte.
+       Default: 4096
+
+udp_wmem_min - INTEGER
+       Minimal size of send buffer used by UDP sockets in moderation.
+       Each UDP socket is able to use the size for sending data, even if
+       total pages of UDP sockets exceed udp_mem pressure. The unit is byte.
+       Default: 4096
+

 CIPSOv4 Variables:
 
 cipso_cache_enable - BOOLEAN
 CIPSOv4 Variables:
 
 cipso_cache_enable - BOOLEAN