[openib-general] [PATCH 0/6] Tranport Neutral Verbs Proposal.

[James Lentini]

On Mon, 31 Jul 2006, Greg Lindahl wrote:

> On Mon, Jul 31, 2006 at 10:24:11AM -0500, Steve Wise wrote:
> 
> > However, the IETF RDMA protocol defines SEND as well as READ, WRITE,
> > etc.  So in my mind, that's all RDMA, not just read and write.
> 
> Well, most people think RDMA means RDMA. The RDMA protocol undoubtedly
> defines SEND/RECV because it's needed in addition to RDMA to get good
> performance. But trying to call all of that RDMA is a marketing slogan.

I agree that the term RDMA SEND is confusing. However, the data in an 
RDMA SEND is deposited directly (zero copy) into the users memory. 
With that in mind, I can understand why the authors of the IETF spec 
termed these operations RDMA SEND/RECV.

> Here's why it's a problem: I've repeatedly seen people try to use RDMA
> (get and put) all the time because they think it must be faster than

I'm assuming RDMA get/put correspond to RDMA READ/WRITE.

> simple send and receive... that's what the slogans tell them. But then
> they discover that they need to use ordinary SEND/RECV for shorter
> messages and for conversations with a lot of participants. 

By ordinary SEND/RECV, do you mean IB/iWARP SEND/RECV or traditional 
(sockets) networking send(2)/recv(2)?

> That's a technical screwup caused by the marketing slogan.

The terms RDMA read and RDMA write are technically accurate. It sounds 
like these developers were misled to believe that using RDMA 
will speed up all communications. Of course that is not true. There 
are situations (e.g. short lived connections) were RDMA may not be 
appropriate. 

> Let's pick symbol names that match our organization name.

Our organization name has more to do with marketing than anything 
else.

> I'm a bit dissappointed that several of you who were at the last 
> Sonoma conference forgot we discussed this in a public session right 
> before the name change. I am not on the steering committee, and 
> wouldn't be surprised if the openrdma domain name issue was the big 
> decider in the name choice, but the wisdom of having RDMA in our 
> name was in doubt for more reasons than just that.

I think either rdmav_ or rdv_ would be ok, but I see how using RDMA 
throughout the API could be confusing.

Perhaps someone can think of a better prefix. How about dav_ (direct 
access verb)?