tcp: document tcp_max_ssthresh (Limited Slow-Start)

[pandora-kernel.git] / Documentation / networking / ip-sysctl.txt

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index ac3b4a7..d3d653a 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -280,6 +280,17 @@ tcp_max_orphans - INTEGER
        more aggressively. Let me to remind again: each orphan eats
        up to ~64K of unswappable memory.
 
+tcp_max_ssthresh - INTEGER
+       Limited Slow-Start for TCP with large congestion windows (cwnd) defined in
+       RFC3742. Limited slow-start is a mechanism to limit growth of the cwnd
+       on the region where cwnd is larger than tcp_max_ssthresh. TCP increases cwnd
+       by at most tcp_max_ssthresh segments, and by at least tcp_max_ssthresh/2
+       segments per RTT when the cwnd is above tcp_max_ssthresh.
+       If TCP connection increased cwnd to thousands (or tens of thousands) segments,
+       and thousands of packets were being dropped during slow-start, you can set
+       tcp_max_ssthresh to improve performance for new TCP connection.
+       Default: 0 (off)
+
 tcp_max_syn_backlog - INTEGER
        Maximal number of remembered connection requests, which are
        still did not receive an acknowledgment from connecting client.