From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shan Wei Subject: [PATCH]tcp: document tcp_max_ssthresh (Limited Slow-Start) Date: Sun, 20 Feb 2011 15:52:41 +0800 Message-ID: <4D60C849.40905@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE To: =?UTF-8?B?SWxwbyBKw6RydmluZW4=?= , David Miller , Network-Maillist , jheffner@psc.edu Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:54574 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751702Ab1BTHze convert rfc822-to-8bit (ORCPT ); Sun, 20 Feb 2011 02:55:34 -0500 Sender: netdev-owner@vger.kernel.org List-ID: =46rom: Ilpo J=C3=A4rvinen Base on Ilpo's patch about documenting tcp_max_ssthresh. (see http://marc.info/?l=3Dlinux-netdev&m=3D117950581307310&w=3D2) According to errata of RFC3742, fix the number of segments increased=20 during RTT time.=20 Just to state the occasion to use this parameter, But about how to set parameter value, maybe some others can do it.=20 Signed-off-by: Ilpo J=C3=A4rvinen Signed-off-by: Shan Wei --- Documentation/networking/ip-sysctl.txt | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-) diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/net= working/ip-sysctl.txt index ac3b4a7..ea78aac 100644 --- 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. =20 +tcp_max_ssthresh - INTEGER + Limited Slow-Start for TCP with large congestion windows (cwnd) defin= ed in + RFC3742. Limited slow-start is a mechanism to limit growth of the cwn= d + on the region where cwnd is larger than tcp_max_ssthresh. TCP increas= es cwnd + by at most tcp_max_ssthresh segments, and by at least tcp_max_ssthres= h/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 ca= n 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. --=20 1.6.3.3