From owner-freebsd-current@FreeBSD.ORG Mon Apr 26 17:25:38 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5559E16A4CE for ; Mon, 26 Apr 2004 17:25:38 -0700 (PDT) Received: from geri.cc.fer.hr (geri.cc.fer.hr [161.53.72.107]) by mx1.FreeBSD.org (Postfix) with ESMTP id 996DC43D41 for ; Mon, 26 Apr 2004 17:25:37 -0700 (PDT) (envelope-from ivoras@fer.hr) Received: from fer.hr (geri.cc.fer.hr [161.53.72.107]) by geri.cc.fer.hr (8.12.9p2/8.12.8) with ESMTP id i3R0Oh1m035428; Tue, 27 Apr 2004 02:24:43 +0200 (CEST) (envelope-from ivoras@fer.hr) Message-ID: <408DA87E.3000603@fer.hr> Date: Tue, 27 Apr 2004 02:25:34 +0200 From: Ivan Voras User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6b) Gecko/20031205 Thunderbird/0.4 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Luigi Rizzo References: <408D85FD.10809@fer.hr> <20040426153919.A74609@xorpc.icir.org> In-Reply-To: <20040426153919.A74609@xorpc.icir.org> X-Enigmail-Version: 0.83.1.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: current@freebsd.org Subject: Re: Dummynet low bandwidth simulation X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 27 Apr 2004 00:25:38 -0000 Luigi Rizzo wrote: > are you sure you aren't running out of mbufs ? > netstat -m should tell you. No, its not mbufs (such messages are shown on the console I believe and I haven't seen them; also, running netstat -m states there's plenty of buffers remaining). > Additionally, note that the 250ms of delay are probably way too much > for your config (you are adding 250ms each way, which makes a 500ms RTT, > not accounting for transmission times -- i think normal values here > are more like 150-200ms rtt), and possibly irrelevant given how > large your queues are -- a full-size packet is 12000 bits or 200ms, > you can have up to 20 queued... Oh sorry, I pasted from a wrong shell script. I've been experimenting with different values and am considering settling at 75ms, queue of 5. I'm still not sure: how does the number of buckets influence the operation? I don't think it's clear to me how would such large queues produce my errors (connection reset by peer & broken pipe). Is this reasoning correct: in the above case, 200ms*20 = 4s, so in the worst case the packet from the end of a queue will travel 4s until it reaches its destination. Is 4s enough for a timeout of some sort? I've tried running on a different machine, running 4.9-release, and there I also get this error (in large numbers): Error: socket: address is unavailable.: Can't assign requested address -- C isn't that hard: void (*(*f[])())() defines f as an array of unspecified size, of pointers to functions that return pointers to functions that return void.