From owner-freebsd-ipfw@FreeBSD.ORG Tue Sep 30 08:16:08 2003 Return-Path: Delivered-To: freebsd-ipfw@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6A3D116A4B3 for ; Tue, 30 Sep 2003 08:16:08 -0700 (PDT) Received: from shellma.zin.lublin.pl (shellma.zin.lublin.pl [212.182.126.68]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2EC934400B for ; Tue, 30 Sep 2003 08:16:03 -0700 (PDT) (envelope-from pawmal-posting@freebsd.lublin.pl) Received: by shellma.zin.lublin.pl (Postfix, from userid 1018) id 2ACBD5F103; Tue, 30 Sep 2003 17:19:10 +0200 (CEST) Date: Tue, 30 Sep 2003 17:19:10 +0200 From: Pawel Malachowski To: freebsd-ipfw@freebsd.org Message-ID: <20030930151910.GB22091@shellma.zin.lublin.pl> References: <0AF1BBDF1218F14E9B4CCE414744E70F1F3F07@exchange.wanglobal.net> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <0AF1BBDF1218F14E9B4CCE414744E70F1F3F07@exchange.wanglobal.net> User-Agent: Mutt/1.4.1i Subject: Re: Queue sizes. X-BeenThere: freebsd-ipfw@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: IPFW Technical Discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Sep 2003 15:16:08 -0000 On Tue, Sep 30, 2003 at 12:43:37AM +0200, Sten Daniel S?rsdal wrote: > I've experimented with various queue sizes to pipes and i just cant figure out a generic algorithm from 10mbit through 64kbit > (10240, 8192, 4096, 2048, 1024, 512, 256, 128, 64 kbit/s). > Does anyone know the most efficient queue size for latency (most important) vs. bulk (must be _roughly_ same before and after) ? > Google doesnt help much (keywords might be wrong?). > I would really appreciate if anyone got any tips/clues? I've found for my own, that usually setting queue (buffer size, it is a bit confusing to call `queue' two things) for about 1/3 of links speed in KBytes is OK. for example, I set queue to 30KBytes for pipe with bw 768kbit/s. When saturated, 768kbit/s (96KB/s) link can transmit 30KB within ~300ms and it is acceptable *for me* (note, this 300ms must be usually doubled because incoming and outgoing traffic have separate pipes). Setting too small queue size can cause problems, for example TCP has problems with packet lossess and data transfer can be lowered twice or even more, I was observing this with WinXP system, this is normal so be carefull and test a lot. -- Paweł Małachowski