[Qemu-devel] virtio-blk throughput

[Prateek Sharma]

Hello everyone,
   I am testing virtio-blk throughput (single thread, using hdparm -tT
). I want to know what is the guest/baremetal sequential read ratio
with the current qemu / qemu-kvm builds.
I have tried with qemu 1.0, 0.15, 0.14.1 , but my guest throughput is
limited to 65 MB/s. Baremetal is at 112 MB/s .

Here is my VM configuration

$QEMU  -cpu core2duo,+vmx  -drive file=$VM_PATH,if=virtio,aio=native
-drive file=viotest.img,if=virtio,index=2 -net tap -net
nic,macaddr=00:01:02:03:04:$VNC_OFFSET -kernel $KERNEL_IMAGE -append
'root=/dev/vda1 rw memmap=10M$100M kmemcheck=on' -m 1000 -vnc
0.0.0.0:$VNC_OFFSET

Is there something wrong in the configuration ? I was hoping
virtio-blk would give ~75% baremetal throughput atleast for large
streaming reads.

Thanks,
Prateek