On Feb 18, 2008 10:43 AM, Erez Zilber <erezz@xxxxxxxxxxxx> wrote: > If you use a high value for FirstBurstLength, all (or most) of your data > will be sent as unsolicited data-out PDUs. These PDUs don't use the RDMA > engine, so you miss the advantage of IB. Hello Erez, Did you notice the e-mail Roland Dreier wrote on Februari 6, 2008 ? This is what Roland wrote: > I think the confusion here is caused by a slight misuse of the term > "RDMA". It is true that all data is always transported over an > InfiniBand connection when iSER is used, but not all such transfers > are one-sided RDMA operations; some data can be transferred using > send/receive operations. Or: data sent during the first burst is not transferred via one-sided remote memory reads or writes but via two-sided send/receive operations. At least on my setup, these operations are as fast as one-sided remote memory reads or writes. As an example, I obtained the following numbers on my setup (SDR 4x network); ib_write_bw: 933 MB/s. ib_read_bw: 905 MB/s. ib_send_bw: 931 MB/s. Bart Van Assche. - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
