[ofa-general] Re: [PATCH RFC] rds: add iwarp support

[Or Gerlitz]

Olaf Kirch wrote:
> As Or already noted, it would be preferable to have IB and iWARP share as much as possible. I understand there probably needs to be a different transport class for iWARP, but I would like iWARP to be some kind of "we do everything like IB except these two little bits" transport.
Just to clarify, the new "fastreg as work requests" API is NOT iWARP 
specific, but rather comply in 95% to both IB and iWARP specs. 
Currently, support for these verbs has been posted only for the Chelsio 
driver (to be merged in 2.6.27-rc1), but Mellanox has made a comment 
over the list that support for the mlx4 is planned.

So the distinction is between devices that

1. don't support any sort of fastreg
2. support the proprietary fmr verbs
3. support the standard fastreg as work request verbs

my understanding is that RDS does not support type one ones, and its a 
question whether maintainance wise, you want to support type two ones.

Other then that fastreg issue, and assuming the credit management issue 
is solved (is it?) is there any difference between IB to iWARP which you 
see as relevant to RDS v3 (p2p + rdma)?

Or.

The 5% difference are things supported by iWARP but not by IB such as 
read-with-invalidate, etc