Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161444AbWASVwM (ORCPT ); Thu, 19 Jan 2006 16:52:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161446AbWASVwM (ORCPT ); Thu, 19 Jan 2006 16:52:12 -0500 Received: from mx.pathscale.com ([64.160.42.68]:34703 "EHLO mx.pathscale.com") by vger.kernel.org with ESMTP id S1161444AbWASVwK (ORCPT ); Thu, 19 Jan 2006 16:52:10 -0500 Subject: Re: [openib-general] Re: RFC: ipath ioctls and their replacements From: "Bryan O'Sullivan" To: Sean Hefty Cc: "Eric W. Biederman" , Andrew Morton , Greg Kroah-Hartman , Roland Dreier , linux-kernel@vger.kernel.org, openib-general@openib.org, "David S. Miller" In-Reply-To: <43CFFFCB.7060002@ichips.intel.com> References: <1137631411.4757.218.camel@serpentine.pathscale.com> <1137688158.3693.29.camel@serpentine.pathscale.com> <43CFDF5F.5060409@ichips.intel.com> <1137696901.3693.66.camel@serpentine.pathscale.com> <43CFFFCB.7060002@ichips.intel.com> Content-Type: text/plain Organization: PathScale, Inc. Date: Thu, 19 Jan 2006 13:52:05 -0800 Message-Id: <1137707525.3693.95.camel@serpentine.pathscale.com> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1334 Lines: 36 On Thu, 2006-01-19 at 13:08 -0800, Sean Hefty wrote: > I'm struggling to understand what your card does then. From this, it sounds > like a standard network card that just happens to use IB physicals. It has typical features of a standard network card, while also supporting direct user access to the hardware. We eschew the offload-as-much-as-possible approach that other vendors take. > Do you just send raw packets? We certainly can do that. The hardware doesn't need to do much more, in fact. > How is the LRH formatted by your card? I.e. what's setting > up the dlid, slid, vl, etc.? This is all done in software. The low-level driver and hardware fill out enough of the IB UD protocol headers to put packets on the wire that an IB switch will route. The higher-level layer is responsible for the full IB protocol suite and the driver-side interfaces to the various OpenIB userspace APIs. > Can your card interoperate with other IB devices > on the network when running in this mode? Yes. It can do both the low-level wonkery and regular IB at the same time.