Re: [PATCH 7/9] IB/core: generic RDMA READ/WRITE API

Christoph Hellwig
2016-03-01T09:13:38Z

On Tue, Mar 01, 2016 at 11:00:11AM +0200, Sagi Grimberg wrote:
>
>>> + if (rdma_rw_use_mr(qp->device, port_num)) {
>>> + ret = rdma_rw_init_mr_wrs(ctx, qp, port_num, sg, sg_offset,
>>> + remote_addr, rkey, dir);
>>
>> At some point I would like the iWARP IO to do no-mr for WRITE/dma_nents
>> == 1, and WRITE/dma_nents <= max_send_sge for the device. I think this
>> will help smaller iSER/NVMEF READ IOPs. I'm testing this out now on the
>> NVMEF code, which is slightly different. If it proves out to better the
>> performance, I'll post a follow-on patch...
>
> Is this possible given that pd->local_dma_lkey has only local
> permissions?

I think he means NVMe / SCSI READ commands, which use RDMA WRITE.
For NVMe / SCSI WRITE commands that use RDMA READ all bets are off
for iWarp, but at least it supports READ W/ INVALIDATE.
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html