From owner-freebsd-net@FreeBSD.ORG Thu Jan 31 08:45:23 2013 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id E315C3C3 for ; Thu, 31 Jan 2013 08:45:23 +0000 (UTC) (envelope-from lars@netapp.com) Received: from mx12.netapp.com (mx12.netapp.com [216.240.18.77]) by mx1.freebsd.org (Postfix) with ESMTP id CD5BC310 for ; Thu, 31 Jan 2013 08:45:23 +0000 (UTC) X-IronPort-AV: E=Sophos;i="4.84,575,1355126400"; d="scan'208";a="14589303" Received: from smtp1.corp.netapp.com ([10.57.156.124]) by mx12-out.netapp.com with ESMTP; 31 Jan 2013 00:45:17 -0800 Received: from vmwexceht03-prd.hq.netapp.com (vmwexceht03-prd.hq.netapp.com [10.106.76.241]) by smtp1.corp.netapp.com (8.13.1/8.13.1/NTAP-1.6) with ESMTP id r0V8jGhl008396; Thu, 31 Jan 2013 00:45:17 -0800 (PST) Received: from SACEXCMBX01-PRD.hq.netapp.com ([169.254.2.54]) by vmwexceht03-prd.hq.netapp.com ([10.106.76.241]) with mapi id 14.02.0328.009; Thu, 31 Jan 2013 00:45:16 -0800 From: "Eggert, Lars" To: "mjl@luckie.org.nz" Subject: Re: high cpu usage on natd / dhcpd Thread-Topic: high cpu usage on natd / dhcpd Thread-Index: AQHN/49K3QG1cuBZpEGa6wjl1WYXnA== Date: Thu, 31 Jan 2013 08:45:14 +0000 Message-ID: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.106.53.51] Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "freebsd-net@freebsd.org" X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 31 Jan 2013 08:45:23 -0000 Hi, > I have a small system running FreeBSD 8.2 that does NAT using ipfw and=20 > natd to systems attached to two interfaces: em0 and wlan0. I have a=20 > dhcpd daemon issuing leases on those interfaces. The system has an em1=20 > interface plugged into a cable modem where it obtains a DHCP lease from=20 > an ISP. >=20 > For some reason, when traffic from the Internet terminates on the system= =20 > itself (I scp a file from the computer) the natd and dhcpd processes=20 > consume significant CPU, and the throughput is less than I expect.=20 > Traffic that passes through to a computer behind the NAT flows without=20 > causing the natd or dhcpd processes to measurably consume CPU. I see exactly the same issue on -STABLE. Have you been able to figure out t= he cause? Thanks, Lars=