Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267984AbUIPLmI (ORCPT ); Thu, 16 Sep 2004 07:42:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267977AbUIPLlg (ORCPT ); Thu, 16 Sep 2004 07:41:36 -0400 Received: from mx1.redhat.com ([66.187.233.31]:43401 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S267992AbUIPLhX (ORCPT ); Thu, 16 Sep 2004 07:37:23 -0400 Message-ID: <41497AEC.1010807@redhat.com> Date: Thu, 16 Sep 2004 07:37:16 -0400 From: Neil Horman User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.0; hi, Mom) Gecko/20020604 Netscape/7.01 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Wes Felter CC: linux-kernel@vger.kernel.org, netdev@oss.sgi.com Subject: Re: The ultimate TOE design References: <4148991B.9050200@pobox.com> <4148A561.5070401@redhat.com> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3746 Lines: 85 Wes Felter wrote: > Neil Horman wrote: > >> Paul Jakma wrote: >> >>> On Wed, 15 Sep 2004, Jeff Garzik wrote: >>> >>>> Put simply, the "ultimate TOE card" would be a card with network >>>> ports, a generic CPU (arm, mips, whatever.), some RAM, and some >>>> flash. This card's "firmware" is the Linux kernel, configured to >>>> run as a _totally indepenent network node_, with IP address(es) all >>>> its own. >>>> >>>> Then, your host system OS will communicate with the Linux kernel >>>> running on the card across the PCI bus, using IP packets (64K fixed >>>> MTU). > > >>> The intel IXP's are like the above, XScale+extra-bits host-on-a-PCI >>> card running Linux. Or is that what you were referring to with >>> " but they are all fairly expensive."? > > >> IBM's PowerNP chip was also very simmilar (a powerpc core with lots of >> hardware assists for DMA and packet inspection in the extended >> register area). Don't know if they still sell it, but at one time I >> had heard they had booted linux on it. > > > An IXP or PowerNP wouldn't work for Jeff's idea. The IXP's XScale core > and PowerNP's PowerPC core are way too slow to do any significant > processing; they are intended for control tasks like updating the > routing tables. All the work in the IXP or PowerNP is done by the > microengines, which have weird, non-Linux-compatible architectures. > I didn't say the assist hardware wouldn't need an extra driver. Its not 100% free, as Jeff proposes, but the CPU portion of these designs is _sufficient_ to run linux, and a driver can be written to drive the remainder of these chips. Its the combination that network device manufacturers design to today: A specialized chip to do L3/L2 forwarding at line rate over a large number of ports, and just enough general purpose CPU to manage the user interface, the forwarding hardware and any overflow forwarding that the forwarding hardware can't deal with quickly. > To do 10 Gbps Ethernet with Jeff's approach, wouldn't you need a 5-10 > GHz processor on the card? Sounds expensive. > To handle port densities that are competing in the market today? Yes, which as I mentioned earlier would price designs like this out of the market. Jeffs idea is a nice one, but it doesn't really fit well with the hardware that networking equipment manufacturers are building today. Take a look at Broadcoms StrataSwitch/StrataXGS lines, or Switchcores Xpeedium processors. These are the sorts of things we have to work with . They provide network stack offload in competitive port densities, but they aren't also general purpose processors. They need a driver to massage their behavior into something more linux friendly. If we could develop an infrastrucutre that made these chips easy to integrate into a platform running linux, linux could quickly come to dominate a large portion of the network device space. Neil > Wes Felter - wesley@felter.org - http://felter.org/wesley/ > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- /*************************************************** *Neil Horman *Software Engineer *Red Hat, Inc. *nhorman@redhat.com *gpg keyid: 1024D / 0x92A74FA1 *http://pgp.mit.edu ***************************************************/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/