On Mon, Jan 24, 2011 at 4:32 PM, Or Gerlitz <ogerl...@voltaire.com> wrote: > David Dillow wrote: >>> if we look on the 50% for SAS/1M IOs that you're presenting, can you tell >>> what made the difference, srp went from sg_tablesize of 255 to 256 so the >>> upper layers where able to provide 1M as one IO > >> This win is from sg_tablesize going from 255 to 256 in this case; the HW >> really likes that better than getting two requests -- one for 1020 KB >> and one for 4 KB. > > Its always nice to find the simplest explanation to the greatest > improvement... going to the 2nd largest gains > >> SAS 2M 520 MB/s 861 MB/s >> SAS 4M 529 MB/s 921 MB/s >> SAS 8M 600 MB/s 951 MB/s > > I wonder what made the difference here? it can't be only the 255 --> 256 > sg_tablesize change, for the 2M case > the change to use 512 pages FMRs could let you use one rkey/fmr for the whole > IO but not for 4M/8M
I think it would be interesting to have performance measurements with a RAM disk as target too because it is hard to tell for someone not familiar with the internals of the target used in this test which performance gain is due to the initiator changes and which is due to the target behavior. Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
