Re: IETF draft: RDMA Protocol Extensions

[Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>]

On 11/29/2013 4:16 AM, Yann Droneaud wrote:
> Hi,
>
> I've just seen the following IETF drafts:
>
> - "RDMA Protocol Extensions", draft-ietf-storm-rdmap-ext-08.txt, by
> Hemal Shah, Felix Marti, Wael Noureddine, Asgeir Eiriksson and Robert 
> Sharp:
>
> http://tools.ietf.org/html/draft-ietf-storm-rdmap-ext-08
>
> "Abstract
>
>    This document specifies extensions to the IETF Remote Direct Memory
>    Access Protocol (RDMAP [RFC5040]). RDMAP provides read and write
>    services directly to applications and enables data to be transferred
>    directly into Upper Layer Protocol (ULP) Buffers without
>    intermediate data copies. The extensions specified in this document
>    provide the following capabilities and/or improvements: Atomic
>    Operations and Immediate Data."
> "
>
> 5. Atomic Operations
> http://tools.ietf.org/html/draft-ietf-storm-rdmap-ext-08#section-5
>
> 6. Immediate Data
> http://tools.ietf.org/html/draft-ietf-storm-rdmap-ext-08#section-6
>
> - "RDMA Protocol Extensions V2", draft-wood-storm-rdmap-ext-v2-00.txt, by
> Donald Wood, Robert Sharp and Kenneth Keels:
>
> http://tools.ietf.org/html/draft-wood-storm-rdmap-ext-v2-00
>
> "
> Abstract
>
>    This document specifies extensions to the IETF Remote Direct Memory
>    Access Protocol and RDMA Protocol Extensions. RDMAP provides read
>    and write services directly to applications and enables data to be
>    transferred directly into Upper Layer Protocol (ULP) Buffers without
>    intermediate data copies. The extensions specified in this document
>    provide the following capabilities and/or improvements to eliminate
>    application visible differences with other RDMA technologies: Send
>    with Immediate Data Operations and a new form of RDMA Read
>    Operation.
> "
>
> 5. Send with Immediate Data Operations:
> http://tools.ietf.org/html/draft-wood-storm-rdmap-ext-v2-00#section-5
>
> 6. RDMA Read V2:
> http://tools.ietf.org/html/draft-wood-storm-rdmap-ext-v2-00#section-6
>
> Is there someone involved in these drafts on the list that could explain
> how it will impact Linux RDMA implementation ?
>

Any iWARP providers that support these will be impacted probably in 
device-specific ways in order to support these new operations.   The 
core iwcm might be impacted, but I can't think of how it would be at 
this point.  I wouldn't think any other core modules will be impacted.

Probably we'll have to come up with some way to allow applications to 
know whether the device supports these features.  Currently most 
applications key on the transport type to decide about whether these 
features are supported or not.  We should allow them to key on the 
feature support instead perhaps.

Steve.
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