From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: Raise initial congestion window size / speedup slow start? Date: Wed, 14 Jul 2010 11:15:53 -0700 (PDT) Message-ID: <20100714.111553.104052157.davem@davemloft.net> References: <4C3D94E3.9080103@wildgooses.com> <4C3DD5EB.9070908@tmr.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: lists@wildgooses.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: davidsen@tmr.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:48897 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751721Ab0GNSPi (ORCPT ); Wed, 14 Jul 2010 14:15:38 -0400 In-Reply-To: <4C3DD5EB.9070908@tmr.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Bill Davidsen Date: Wed, 14 Jul 2010 11:21:15 -0400 > You may have to go into /proc/sys/net/core and crank up the > rmem_* settings, depending on your distribution. You should never, ever, have to touch the various networking sysctl values to get good performance in any normal setup. If you do, it's a bug, report it so we can fix it. I cringe every time someone says to do this, so please do me a favor and don't spread this further. :-) For one thing, TCP dynamically adjusts the socket buffer sizes based upon the behavior of traffic on the connection. And the TCP memory limit sysctls (not the core socket ones) are sized based upon available memory. They are there to protect you from situations such as having so much memory dedicated to socket buffers that there is none left to do other things effectively. It's a protective limit, rather than a setting meant to increase or improve performance. So like the others, leave these alone too.