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

[Anthony Liguori]

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