From owner-freebsd-hackers@FreeBSD.ORG Sat Feb 28 18:23:46 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DB8D216A4CE for ; Sat, 28 Feb 2004 18:23:46 -0800 (PST) Received: from aries.ai.net (aries.ai.net [205.134.163.4]) by mx1.FreeBSD.org (Postfix) with ESMTP id 871E943D1D for ; Sat, 28 Feb 2004 18:23:46 -0800 (PST) (envelope-from deepak@ai.net) Received: from ai.net (mikej@pool-151-200-114-38.res.east.verizon.net [151.200.114.38]) by aries.ai.net (8.9.3/8.9.3) with ESMTP id VAA12455; Sat, 28 Feb 2004 21:23:45 -0500 (EST) (envelope-from deepak@ai.net) Message-ID: <40414D2F.6070604@ai.net> Date: Sat, 28 Feb 2004 21:23:43 -0500 From: Deepak Jain User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6) Gecko/20040113 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Don Bowman References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: freebsd-hackers@freebsd.org Subject: Re: em0, polling performance, P4 2.8ghz FSB 800mhz X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 29 Feb 2004 02:23:47 -0000 Don Bowman wrote: >>I have a machine running 4.9. P4 2.8Ghz, 800mhz bus, Intel PRO/1000 >>ethernet connected to a Cisco, both sides are locked to 1000/FD. >> >>The kernel has HZ=1000, and DEVICE_POLLING, IPFW, DUMMYNET, >>etc. After >>only a few minutes of run time under an attack ~90,000 pps. >>The attack >>has been limited at the router to JUST incoming TCP port 80 inbound >>traffic. I don't know why the machine is having such a hard >>time under >>the load. The cpu shows it is >90% idle even under the worst of the >>attack. What am I doing wrong? > > > I think there's a problem with CPU time not getting properly > accounted for in device polling, so it may be busier than you think. > > For this scenario, i would set net.inet.tcp.blackhole=2. You > might be spending a lot of time creating the ICMP unreachable > messages, rather than in the network driver (where device polling > would help). > I'd like to know more about the CPU time idea. I have net.inet.udp.blackhole=2 and net.inet.tcp.blackhole=2 because I saw a lot of dstunreachable packets out. The system can hyperthread, but I thought the singlethreading of polling might have been an issue, so I recompiled the kernel without SMP. DJ