At 03:14 AM 6/20/2007, ncic wrote: >why didn't they support ib with sdp?
There are two main answers. The first is licensing. SDP licensing is wrapped up in a Microsoft intellectual property issue, this has prevented its inclusion in some kernels, including Linux. So, upper layers cannot depend in its presence. The second, speaking for NFS at least, is performance. SDP relies heavily on additional setup exchanges and RDMA Read for transparency, these negatively impact performance. With minimal additional work, the same unmodified upper layer NFS filesystem code can use native RDMA exchanges via the RPC layer and achieve truly excellent performance. Check out Helen Chen's presentation from the recent Sonoma workshop. <http://www.openfabrics.org/archives/spring2007sonoma/Tuesday%20May%201/Helen%20Chen%20NFS%20over%20RDMA%20-%20IB%20and%20iWARP-5.pdf> In the NFS case, the protocol is on a standards track and published in the IETF (I'm the primary author), I'm hopeful that the edits I'm currently preparing for publication will be finalized around the July meeting. And, we have complete implementations of both client and server in both Linux and OpenSolaris. For transparent mode, don't discount ordinary sockets over a connected mode IPoIB approach. The performance is very good, and provides a fully transparent solution to all upper layers. RDMA is better though, by (greatly) reducing overhead. Tom. _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
