From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. Bruce Fields" Subject: [PATCH] Documentation: clarify tcp_{r,w}mem sysctl docs Date: Thu, 10 Jul 2008 16:05:10 -0400 Message-ID: <20080710200510.GE27734@fieldses.org> References: <20080708134845.2372a483@speedy> <20080708180500.e8a61231.billfink@mindspring.com> <20080709052534.GA8157@2ka.mipt.ru> <20080709014758.d59be0d8.billfink@mindspring.com> <20080709060341.GA29743@2ka.mipt.ru> <20080709181122.GB488@fieldses.org> <20080709184329.GC5383@2ka.mipt.ru> <20080709222802.GK488@fieldses.org> <20080710010649.GA28491@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Bill Fink , Stephen Hemminger , Roland Dreier , David Miller , aglo@citi.umich.edu, shemminger@vyatta.com, netdev@vger.kernel.org, rees@umich.edu, Evgeniy Polyakov To: Jonathan Corbet Return-path: Received: from mail.fieldses.org ([66.93.2.214]:50658 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753301AbYGJUFS (ORCPT ); Thu, 10 Jul 2008 16:05:18 -0400 Content-Disposition: inline In-Reply-To: <20080710010649.GA28491@2ka.mipt.ru> Sender: netdev-owner@vger.kernel.org List-ID: From: J. Bruce Fields Date: Wed, 9 Jul 2008 18:28:48 -0400 Fix some of the defaults and attempt to clarify some language. Signed-off-by: J. Bruce Fields Cc: Evgeniy Polyakov --- Documentation/networking/ip-sysctl.txt | 26 +++++++++++++++----------- 1 files changed, 15 insertions(+), 11 deletions(-) On Thu, Jul 10, 2008 at 05:06:50AM +0400, Evgeniy Polyakov wrote: > On Wed, Jul 09, 2008 at 06:28:02PM -0400, J. Bruce Fields > (bfields@fieldses.org) wrote: > > OK, thanks. Would the following be any more clearer and/or > > accurate? > > Looks good, thank you :) > It is likely the first ever mention of the fact, that SO_RECV/SNDBUF > disables autotuning. OK! Uh, I'm assuming Jon Corbet's documentation tree would be a reasonable route to submit this by.... --b. diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 17a6e46..a22af04 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -336,7 +336,7 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max pressure. Default: 8K - default: default size of receive buffer used by TCP sockets. + default: initial size of receive buffer used by TCP sockets. This value overrides net.core.rmem_default used by other protocols. Default: 87380 bytes. This value results in window of 65535 with default setting of tcp_adv_win_scale and tcp_app_win:0 and a bit @@ -344,8 +344,10 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max max: maximal size of receive buffer allowed for automatically selected receiver buffers for TCP socket. This value does not override - net.core.rmem_max, "static" selection via SO_RCVBUF does not use this. - Default: 87380*2 bytes. + net.core.rmem_max. Calling setsockopt() with SO_RCVBUF disables + automatic tuning of that socket's receive buffer size, in which + case this value is ignored. + Default: between 87380B and 4MB, depending on RAM size. tcp_sack - BOOLEAN Enable select acknowledgments (SACKS). @@ -419,19 +421,21 @@ tcp_window_scaling - BOOLEAN Enable window scaling as defined in RFC1323. tcp_wmem - vector of 3 INTEGERs: min, default, max - min: Amount of memory reserved for send buffers for TCP socket. + min: Amount of memory reserved for send buffers for TCP sockets. Each TCP socket has rights to use it due to fact of its birth. Default: 4K - default: Amount of memory allowed for send buffers for TCP socket - by default. This value overrides net.core.wmem_default used - by other protocols, it is usually lower than net.core.wmem_default. + default: initial size of send buffer used by TCP sockets. This + value overrides net.core.wmem_default used by other protocols. + It is usually lower than net.core.wmem_default. Default: 16K - max: Maximal amount of memory allowed for automatically selected - send buffers for TCP socket. This value does not override - net.core.wmem_max, "static" selection via SO_SNDBUF does not use this. - Default: 128K + max: Maximal amount of memory allowed for automatically tuned + send buffers for TCP sockets. This value does not override + net.core.wmem_max. Calling setsockopt() with SO_SNDBUF disables + automatic tuning of that socket's send buffer size, in which case + this value is ignored. + Default: between 64K and 4MB, depending on RAM size. tcp_workaround_signed_windows - BOOLEAN If set, assume no receipt of a window scaling option means the -- 1.5.5.rc1