On 7/24/2015 10:24 PM, Jason Gunthorpe wrote:
On Fri, Jul 24, 2015 at 01:48:09PM -0500, Steve Wise wrote:
The use of FRWR for RDMA READ should be iWarp specific, IB shouldn't
pay that overhead. I am expecting to see a cap_rdma_read_rkey or
something in here ?
Ok. But cap_rdma_read_rkey() doesn't really describe the
requirement. The requirement is rkey + REMOTE_WRITE. So it is more
like rdma_cap_read_requires_remote_write() which is ugly and too
long (but descriptive)...
I don't care much what name you pick, just jam something like this in
the description
I think we can just do if (signature || iwarp) use fastreg else
use local_dma_lkey.
If set then RDMA_READ must be performed by mapping the local
buffers through a rkey MR with ACCESS_REMOTE_WRITE enabled.
The rkey of this MR should be passed in as the sg_lists's lkey for
IB_WR_RDMA_READ_WITH_INV.
I think this would be an incremental patch and not as part of iwarp
support.
Question though, wouldn't it be better to do a single RDMA_READ to say
4 registered keys rather than RDMA_READ_WITH_INV for each?
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