At 03:12 PM 5/9/2006, Roland Dreier wrote: >BTW, does Mellanox (or anyone else) have any numbers showing that >using FMRs makes any difference in performance on a semi-realistic benchmark?
Not me. Using the current FMRs to register/deregister windows for each NFS/RDMA operation yields only a slight performance improvement over ib_reg_phys_mr(), and I suspect this is mainly from the fact that FMRs are page-rounded. Additionally, I find that the queuepair (or perhaps the completion queue) seems to hang unpredictably, new events get stuck, only to flush after the upper layer times out and closes the connection. What I really don't like about the current FMRs is that they seem to be optimized only for lazy-deregistration, the fmr pools attempt to defer the deregistration somewhat indefinitely. This is an enormous security hole, and pretty much defeats the point of dynamic registration. The NFS/RDMA client has full-physical mode for users that want speed in well-protected environments. And it's a LOT faster. I am planning to test this some more in the next few weeks, but what I'd really like to see is an IBTA 1.2-compliant implementation, and one that operated on work queue entries (not synchronous verbs). Is that being worked on? Tom. _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
