On Thu, 2012-06-14 at 09:30 +0100, Stefan Hajnoczi wrote: > On Wed, Jun 13, 2012 at 11:13 AM, mengcong <m...@linux.vnet.ibm.com> wrote: > > seq-read seq-write rand-read rand-write > > 8k 256k 8k 256k 8k 256k 8k 256k > > ---------------------------------------------------------------------------- > > bare-metal 67951 69802 67064 67075 1758 29284 1969 26360 > > tcm-vhost-iblock 61501 66575 51775 67872 1011 22533 1851 28216 > > tcm-vhost-pscsi 66479 68191 50873 67547 1008 22523 1818 28304 > > virtio-blk 26284 66737 23373 65735 1724 28962 1805 27774 > > scsi-disk 36013 60289 46222 62527 1663 12992 1804 27670 > > > > > unit: KB/s > > seq-read/write = sequential read/write > > rand-read/write = random read/write > > 8k,256k are blocksize of the IO > > What strikes me is how virtio-blk performs significantly worse than > bare metal and tcm_vhost for seq-read/seq-write 8k. The good > tcm_vhost results suggest that the overhead is not the virtio > interface itself, since tcm_vhost implements virtio-scsi. > > To drill down on the tcm_vhost vs userspace performance gap we need > virtio-scsi userspace results. QEMU needs to use the same block > device as the tcm-vhost-iblock benchmark. > > Cong: Is it possible to collect the virtio-scsi userspace results > using the same block device as tcm-vhost-iblock and -drive > format=raw,aio=native,cache=none? >
virtio-scsi-raw 43065 69729 52052 67378 1757 29419 2024 28135 qemu ....\ -drive file=/dev/sdb,format=raw,if=none,id=sdb,cache=none,aio=native \ -device virtio-scsi-pci,id=mcbus \ -device scsi-disk,drive=sdb there is only one scsi HBA. /dev/sdb is the disk on which all tests have been done. Is this what you want? Cong Meng > Stefan >
