From owner-freebsd-ipfw@FreeBSD.ORG Tue Feb 21 17:42:03 2006 Return-Path: X-Original-To: freebsd-ipfw@freebsd.org 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 8352216A420 for ; Tue, 21 Feb 2006 17:42:03 +0000 (GMT) (envelope-from rizzo@icir.org) Received: from xorpc.icir.org (xorpc.icir.org [192.150.187.68]) by mx1.FreeBSD.org (Postfix) with ESMTP id D9B9B43D48 for ; Tue, 21 Feb 2006 17:42:02 +0000 (GMT) (envelope-from rizzo@icir.org) Received: from xorpc.icir.org (localhost [127.0.0.1]) by xorpc.icir.org (8.12.11/8.12.11) with ESMTP id k1LHg2np066684; Tue, 21 Feb 2006 09:42:02 -0800 (PST) (envelope-from rizzo@xorpc.icir.org) Received: (from rizzo@localhost) by xorpc.icir.org (8.12.11/8.12.3/Submit) id k1LHg2Qj066683; Tue, 21 Feb 2006 09:42:02 -0800 (PST) (envelope-from rizzo) Date: Tue, 21 Feb 2006 09:42:02 -0800 From: Luigi Rizzo To: Donald Baud Message-ID: <20060221094202.H64136@xorpc.icir.org> References: <20060221082529.B64136@xorpc.icir.org> <20060221163737.31550.qmail@web37411.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <20060221163737.31550.qmail@web37411.mail.mud.yahoo.com>; from donaldbaud@yahoo.com on Tue, Feb 21, 2006 at 08:37:37AM -0800 Cc: freebsd-ipfw@freebsd.org Subject: Re: Patch to add burst to dummynet ? X-BeenThere: freebsd-ipfw@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: IPFW Technical Discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Feb 2006 17:42:03 -0000 On Tue, Feb 21, 2006 at 08:37:37AM -0800, Donald Baud wrote: ... > > if you see just one line above your patch, > > len_scaled is computed as > > > > int len_scaled = p->bandwidth ? len*8*hz : 0 > > ; > > > > so your '100000' correspond (with HZ=1000) to an > > actual burst > > of 100 bits or 12.5 bytes so hardly measurable. > > secondly, as i said the throughput is limited by > > many many factors > > even without dummynet (or just because you have > > traffic going through > > other pipes, etc.). > > > > finally, i don't know how wget computes times so it > > may > > be correct or not, i have no idea. since many > > programs > > do wrong things in computing bandwidths i wouldn't > > give for granted that wget is correct in all > > situations. > > > > bye > > luigi > > > > > > > I even commented out: > > > /* > > > if (len_scaled > q->numbytes) > > > break ; > > > */ > > > While I would have expected full throughput, I got > > > only ~10X the speed of the pipe: > > > > > > 0K .......... .......... 0% 8.30 KB/s > > > 50K .......... .......... 1% 20.70 KB/s > > > 100K .......... .......... 2% 13.80 KB/s > > > 150K .......... .......... 3% 13.80 KB/s > > > > > Let me ask my question differently then, do you think > it is possible to bypass the pipe restriction (i.e. > burst) for say the first 100KBytes ? yes if you put a sufficiently large number in the line to patch (ideally a configurable parameter). of course you'll never go faster than your connection allows without dummynet, and furthermore, 100k are way beyond the amount of buffering that the socket or ipintrq give you by default. you are likely to be slowed down by any of these things. i think i have said all i could on the subject cheers luigi > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com