Bart Van Assche wrote: > On Jan 24, 2008 8:06 AM, Robin Humble <robin.humble+stgt at anu.edu.au> wrote: > >>On Tue, Jan 22, 2008 at 01:32:08PM +0100, Bart Van Assche wrote: >> >>>............................................................................................. >>>. . STGT read SCST read . STGT read SCST read . >>>. . performance performance . performance performance . >>>. . (0.5K, MB/s) (0.5K, MB/s) . (1 MB >MB/s) (1 MB, MB/s) . >>>............................................................................................. >>>. Ethernet (1 Gb/s network) . 77 78 . 77 89 . >>>. IPoIB (8 Gb/s network) . 163 185 . 201 239 . >>>. iSER (8 Gb/s network) . 250 N/A . 360 N/A . >>>. SRP (8 Gb/s network) . N/A 421 . N/A 683 . >>>............................................................................................ >> > > Results with /dev/ram0 configured as backing store on the target (buffered I/O): > Read Write Read Write > performance performance performance performance > (0.5K, MB/s) (0.5K, MB/s) (1 MB, MB/s) (1 MB, MB/s) > STGT + iSER 250 48 349 781 > SCST + SRP 411 66 659 746 Ib_rdma_bw now reports 933 MB/s on the same system, correct? Those ~250MB/s difference is what you will gain with zero-copy IO implemented and what STGT with the current architecture has no chance to achieve. > Results with /dev/ram0 configured as backing store on the target (direct I/O): > Read Write Read Write > performance performance performance performance > (0.5K, MB/s) (0.5K, MB/s) (1 MB, MB/s) (1 MB, MB/s) > STGT + iSER 7.9 9.8 589 647 > SCST + SRP 12.3 9.7 811 794 > > Bart. > |