[dm-devel] Re: I/O bandwidth control on KVM

[Anthony Liguori <anthony codemonkey ws>]

Avi Kivity wrote:
> Anthony Liguori wrote:
> > If you are using virtio drivers in the guest (which I presume you are 
> > given the reference to /dev/vda), try using the following -drive syntax:
> >
> > -drive file=/dev/mapper/ioband1,if=virtio,boot=on,cache=off
> >
> > This will force the use of O_DIRECT.  By default, QEMU does not open 
> > with O_DIRECT so you'll see page cache effects.
> >
> >   
>
> Good point.  But IIRC cache=off is not limited to virtio?

Nope.  I just wanted to give the exact syntax to use and it looked like 
he was using virtio.

Regards,

Anthony Liguori