From owner-freebsd-net@FreeBSD.ORG Tue Jun 21 14:52:52 2005 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 25BF216A41C for ; Tue, 21 Jun 2005 14:52:52 +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 0DF9943D1D for ; Tue, 21 Jun 2005 14:52:52 +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 j5LEqlQu063812; Tue, 21 Jun 2005 07:52:47 -0700 (PDT) (envelope-from rizzo@xorpc.icir.org) Received: (from rizzo@localhost) by xorpc.icir.org (8.12.11/8.12.3/Submit) id j5LEqlUF063811; Tue, 21 Jun 2005 07:52:47 -0700 (PDT) (envelope-from rizzo) Date: Tue, 21 Jun 2005 07:52:47 -0700 From: Luigi Rizzo To: Pieter de Boer Message-ID: <20050621075247.D63359@xorpc.icir.org> References: <42B722EF.2090203@thedarkside.nl> <20050620135044.B35720@xorpc.icir.org> <42B731CD.1040104@thedarkside.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <42B731CD.1040104@thedarkside.nl>; from pieter@thedarkside.nl on Mon, Jun 20, 2005 at 11:14:53PM +0200 Cc: freebsd-net@freebsd.org Subject: Re: Issues with a Large Fat pipe Network simulation X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Jun 2005 14:52:52 -0000 On Mon, Jun 20, 2005 at 11:14:53PM +0200, Pieter de Boer wrote: > Luigi Rizzo wrote: ... > However.. when I deleted the pipe rules on 'network', the speed suddenly > went up to around 800mbit/s too! I remade them, and voila, 200mbit/s. network emulation is a tricky job :) in any case i believe what happens is the following. The pipe has a default size of 50 slots, which at 1500 bytes is little above 64k. If the sender is bursting a large number of packets, it may well overflow the pipe's queue causing a backoff (which may simply be immediate, or delayed, depending on how you configure various things). I believe setting the queue size in the pipe to a value larger than the window should fix things. can you confirm that ? cheers luigi > So apparantly it's an issue in the dummynet configuration I have. So, to > reiterate: > > On 'network': > pipe 1 from client to server via em0 > pipe 2 from server to client via em1 > allow ip from any to any i am > Will give me 200MBit/s when using 128KB window sizes, but 800MBit/s when > using 64KB window sizes. > > On 'network': > allow ip from any to any > > Will give me 800Mbit/s when using 64KB or 128KB window sizes. I haven't > configured the pipes in any way, though. > > > So it appears it's due to the 'network' box afterall.. > > -- > Pieter