[PATCH RFC 20/21] conf: Add possibility to configure multiple iothreads per disk

[Stefan Hajnoczi]

Hi Peter,

> +   -  The optional ``iothreads`` sub-element allows specifying multiple IOThreads
> +      via the ``iothread`` sub-element with attribute ``id``  the disk will use
> +      for I/O operations. Optionally the ``iothread`` element can have multiple
> +      ``queue`` subelements specifying that given iothread should be used to
> +      handle given queues. :since:`Since XXXXXX`.

Although this says that the ``queue`` sub-elements are optional, it
may be clearer to add another sentence that explains the device will
automatically assign virtqueues to the given ``iothread`` sub-elements
when ``queue`` is not given. That answers the question of "what is the
behavior of omitting ``queue``?".

> +        <driver name='qemu' queues='2'>
> +          <iothreads>
> +            <iothread id='1'>
> +              <queue id='1'/>
> +            </iothread>
> +            <iothread id='2'>
> +              <queue id='1'/>
> +            </iothread>

Each queue can only be assigned to 1 IOThread, so <queue id='1'/>
cannot be assigned to multiple IOThreads.

Thank you,
Stefan