From owner-freebsd-net@FreeBSD.ORG Mon Nov 2 13:40:07 2009 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8CCB010656A4 for ; Mon, 2 Nov 2009 13:40:07 +0000 (UTC) (envelope-from barney_cordoba@yahoo.com) Received: from web63908.mail.re1.yahoo.com (web63908.mail.re1.yahoo.com [69.147.97.123]) by mx1.freebsd.org (Postfix) with SMTP id 34FBD8FC08 for ; Mon, 2 Nov 2009 13:40:07 +0000 (UTC) Received: (qmail 86516 invoked by uid 60001); 2 Nov 2009 13:40:06 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1257169206; bh=yXaG+0O4/0mN3lyVzHA6kd0SrAvSZ7eMMLFenMqfNZ4=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=1o5ew6/tb+fKJOsQPX6aG3UOGd4J+mdB9CmX1jxdY0Driwp4xhxTE3/qSirW3AvmhqLIYO6VhxGkc5e20lYyVh6VgN1pUvx9Gm9IUjtUZmTbqLJDrAydbILwD2OY9EOvwUVBO/ZQVGi8G7iLfoROStlZwATKYZ0lOUWs0wEHFYU= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=4ZqO70z+tKgHY1vei+64jDyIdWYwEzK/qIrkFLsTbzZsBznYxe0EpxQ/DgGy2/PMJNuarlH8cfD5iWWulXOHYG7TKmtDZZRHJe7Rs4ospcj2Efcpr+/g5LpFeYznAqaA73+nLyeXblZSB7eWrhjnUEhWsTKcMF6ujoqlHnj52s4=; Message-ID: <274298.85978.qm@web63908.mail.re1.yahoo.com> X-YMail-OSG: BQIC6qEVM1mEDT0tRq2sW3K.yG71LNomDt2Z36yFO3U6u59aU4FjfDW.Iwdie43Wccw8meVKZkur.myDHN8sseizEC_6R7McwlLuukK4EcMcHfS4joQFrKaKa7fcaal7Q_pATqzSfqWgKaCTISKpEeUATbKRpRXgyNB_brMBgiLcxmhLLoNVJrUN2Bn42CQNjr.17lBBMg3KIcOFwWvrVXLtrcyhHhTWuiXByVYEnqriV5a_rqA64ERqT2JhqF0UkHurJetBZA7onjkkrvfSB5ECMK7DkRk5sw9hSh5q1JOYaRDajgmcb9KDKt6OwedCMFrZcenwEfXbcsqqeXrON0yNWEtkqinB2UJSa.fk9gMfReeMRhChwPwIuIgp1uTlvsksctoqu6habRXXPrVqs0iTSfDnUk_s5rVOs.css6fz Received: from [98.203.21.152] by web63908.mail.re1.yahoo.com via HTTP; Mon, 02 Nov 2009 05:40:05 PST X-Mailer: YahooMailClassic/7.0.14 YahooMailWebService/0.7.361.4 Date: Mon, 2 Nov 2009 05:40:05 -0800 (PST) From: Barney Cordoba To: freebsd-net@freebsd.org, rihad In-Reply-To: <4ADDDA2C.3020206@mail.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Subject: Re: dummynet dropping too many packets 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: Mon, 02 Nov 2009 13:40:07 -0000 --- On Tue, 10/20/09, rihad wrote: > From: rihad > Subject: Re: dummynet dropping too many packets > To: freebsd-net@freebsd.org > Date: Tuesday, October 20, 2009, 11:41 AM > I'm so happy today: finally running a > "ifp->if_snd.ifq_drv_maxlen = 4096;" and HZ=4000 kernel > with 4100+ online users @500+ mbps, and, most importantly, > with absolutely 0 drops since boot time! ;-) Even if drops > do come in, I'll know where to look first. I'd like to > express my gratitude to Robert Watson for pointing out the > "ifnet transmit queue sizes" issue, to others who suggested > the problem might be in dummynet's burstiness, and yet to > others who tried hard to help with other suggestions. Thank > you, folks! Tomorrow I'm going to suggest to my boss to > donate some $$$ to the FreeBSD Foundation: http://www.freebsdfoundation.org/donate/ Seems to me that spending money on a real packetshaper would be a better investment than donating to compromise on the free stuff (not that I'd want to discourage anyone from contributing to FreeBSD generally). Your problem is that at high traffic levels you need to reduce traffic flows, not just delay it as dummynet does. The entire point of traffic shaping is to smooth out your traffic flows; not to make it so choppy that you have packets sitting in a transmit queue for 1/2 millisecond in addition to the dummynet delays. While dummynet may not be dropping packets, you have packets being dropped in TCP stacks throughout your customer base, most likely. Barney