[Qemu-devel] IO performance test on the tcm-vhost scsi

[mengcong <mc@linux.vnet.ibm.com>]

Hi folks, I did an IO performance test on the tcm-vhost scsi. I want to share 
the test result data here.


                    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

In tcm-vhost-iblock test, the emulate_write_cache attr was enabled.
In virtio-blk test, cache=none,aio=native were set.
In scsi-disk test, cache=none,aio=native were set, and LSI HBA was used.

I also tried to do the test with a scsi-generic LUN (pass through the 
physical partition /dev/sgX device). But I couldn't setup it
successfully. It's a pity.

Benchmark tool: fio, with ioengine=aio,direct=1,iodepth=8 set for all tests.
kvm vm: 2 cpus and 2G ram

thanks.
Meng Cong.