From owner-freebsd-hackers@FreeBSD.ORG Sat Feb 12 02:02:24 2011 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0A8C2106566C for ; Sat, 12 Feb 2011 02:02:24 +0000 (UTC) (envelope-from santosh@fastsoft.com) Received: from hq-es.fastsoft.com (hq-es.fastsoft.com [38.102.243.86]) by mx1.freebsd.org (Postfix) with ESMTP id DEF188FC08 for ; Sat, 12 Feb 2011 02:02:22 +0000 (UTC) X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Date: Fri, 11 Feb 2011 17:50:16 -0800 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: ixgbe DMA question Thread-Index: AcvKVzI4leMo3PwkQl6kXdO3C585bg== From: "Santosh Rao Gururajan" To: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: ixgbe DMA question X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 12 Feb 2011 02:02:24 -0000 I have a host machine with 2 ixgbe NICs. I am trying to pass the frames from one NIC to the other with the lowest possible overhead to the host (high speed bridge). I am wondering if I can do a rx-ring to tx-ring DMA copy without creating a mbuf on the host. Is that possible? What are the risks? Thanks, -santosh