From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Wise Subject: Re: software iwarp stack update Date: Wed, 22 Sep 2010 15:42:18 -0500 Message-ID: <4C9A6A2A.2020509@opengridcomputing.com> References: <1285187710.1849.82.camel@haakon2.linux-iscsi.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1285187710.1849.82.camel@haakon2.linux-iscsi.org> Sender: netdev-owner@vger.kernel.org To: "Nicholas A. Bellinger" Cc: Bernard Metzler , linux-rdma@vger.kernel.org, netdev@vger.kernel.org, David Miller , Matthew Wilcox , Andi Kleen List-Id: linux-rdma@vger.kernel.org On 09/22/2010 03:35 PM, Nicholas A. Bellinger wrote: > On Wed, 2010-09-22 at 10:19 +0200, Bernard Metzler wrote: > >> Earlier this year, we announced the availability of an open source, >> full software implementation of the iWARP RDMA protocol stack - see >> my email "software iwarp stack" from March 14th at the linux-rdma list >> (http://www.mail-archive.com/linux-rdma@vger.kernel.org/msg02940.html) >> While since then working on performance and stability, we provided >> some source code updates. Current user and kernel code is available at >> gitorious.org/softiwarp. Please see the CHANGES file in the >> kernel/ directory for a summary of the most recent changes. >> >> For more convenient testing, the latest update now allows for a >> stand-alone build of the kernel module without full kernel source >> code access. We tested the code with kernel version 2.6.34. If >> you are interested in a full software RDMA stack on Ethernet, >> please try it out. >> >> In the hope of providing useful information, I put >> netdev@vger.kernel.org on copy. Subscribers of this list, >> please put me on private cc in case you reply or comment, since >> I am not subscribed to the list. >> We would be more than happy if you netdev folks would consider >> a hardware independent RDMA kernel service as something useful and >> potentially to be integrated into the mainline network stack. >> >> Why might it be useful? >> A software RDMA stack makes the semantic advantages of >> asynchronous and one-sided communication available while obsoleting >> the need to deploy dedicated RDMA hardware or any protocol offloading >> (while not matching the lowest delay numbers of real RDMA hardware). >> Implementing the IETF's iWARP protocol stack on top of TCP kernel >> sockets, softiwarp integrates with the open fabrics environment >> and thus exports the RDMA kernel and user verbs interface. >> >> The efficiency of the Linux TCP/IP network stack together with intrinsic >> advantages of the RDMA communication model (async. posting of work >> and reaping of work completions, transfer of send buffer ownership >> to the kernel which enables zero copy transmit, peer data placement >> without application scheduling, one-sided remote read operations etc.) >> can result in improved application-to-application performance and >> less CPU load, while using the unchanged kernel TCP stack. >> >> A software RDMA stack might promote wider RDMA deployment, >> since when using the host TCP stack, it enables RDMA semantic >> independent of dedicated hardware. softiwarp peers with real >> RNICs (tested with Chelsio's T3 adapter). >> >> softiwarp is still work in progress and we are very thankful for any >> suggestions/comments/bug reports. Please advise how we should proceed >> to bring the stack further to your attention. Would it be useful to >> provide patches against the current stable kernel version or the next >> release candidate? >> >> > Hi Bernard, > > So what I would recommend doing here to make things more appealing to > DaveM and other interested NetDev folks would be to clone a seperate > tree from the net-2.6.git or net-next-2.6.git repositories and include > the softiwarp/kernel.git code into a fresh 'in-kernel' clone tracking > the latest netdev code, and then keep git rebase'ing against DaveM's > last changes and update your local tree to the lastest netdev code. > > Of course you will want to remove all of the 'out of tree' LINUX_VERSION > build macros and any other legacy bits to follow mainline kernel > convention for your 'in-kernel' softiwarp tree. > > And then post a patch series for review. Steve.