Re: Using tools such as ionice inside guests

Paolo Bonzini
2016-05-20T10:35:52Z

On 19/05/2016 22:12, Christian Borntraeger wrote:
> On 05/18/2016 07:12 PM, Paolo Bonzini wrote:
>>
>>
>> On 18/05/2016 18:26, Emmanuel Lacour wrote:
>>> Thanks, it's a bad news for us :(
>>>
>>> I will try to play with cgroups io throttling to limit by iops or bytes
>>> read, but it'll be a hard limit rather than a priority :(
>>
>> That probably won't work either, but you can use io throttling on the
>> host too.
>>
>>> Do you think there could be back some io priority throttling in not so
>>> far future kernels?
>>
>> I wouldn't oppose a patch to add back the non-mq path, but as far as I
>> know nobody is working on it. It's not hard and I can help if you need
>> guidance.
>>
>> Adding I/O scheduler support to blk-mq has been promised for at least a
>> year now, but I'm not aware of which kernel release might have the work.
>> It's not even been submitted to LKML, so I guess it's quite far away.
>
> What actually happened to the virtio-blk multiqueue support in QEMU?

The guy who submitted the patch for the "fake" virtio-blk multiqueue
(backed by a single iothread) disappeared. "Real" virtio-blk multiqueue
is at least 80 patches away (70 of those have been written :)).

However, multiqueue is independent from Emmanuel's problem.

Thanks,

Paolo