Re: software iwarp stack update

[Steve Wise <swise@opengridcomputing.com>]

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.