[libvirt] [PATCHv2 8/8] virtio-rng: Add rate limiting options for virtio-RNG

Eric Blake eblake at redhat.com
Sat Feb 23 00:33:50 UTC 2013


On 02/21/2013 07:47 AM, Peter Krempa wrote:
> Qemu's implementation of virtio RNG supports rate limiting of the
> entropy used. This patch exposes the option to tune this fucntionality.

s/fucntionality/functionality/

> 
> This patch is based on qemu commit 904d6f588063fb5ad2b61998acdf1e73fb4
> 
> The rate limiting is exported in the XML as:
> <devices>
>   ...
>   <rng model='virtio'>
>     <rate period='1234'>4321</rate>

So period='nnn', if provided, is in milliseconds?

>     <backend model='random'/>
>   </rng>
>   ...
> ---
> 
> Notes:
>     Version 2:
>     - Qemu uses bytes/period, adapt the value according to that
> 

> @@ -4315,6 +4316,14 @@ qemu-kvm -net nic,model=? /dev/null
>            <li>'virtio' — supported by qemu and virtio-rng kernel module</li>
>          </ul>
>        </dd>
> +      <dt><code>rate</code></dt>
> +      <dd>
> +        <p>
> +          The rate parameter allows to limit the rate that the entropy can be
> +          read from the source. The value is in bits that the device is allowed
> +          to read in the selected period. The default period is 1000ms or 1 second.
> +        </p>

This documentation didn't quite make it clear that 'period' is an
optional attribute in milliseconds.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 621 bytes
Desc: OpenPGP digital signature
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20130222/ab2cd5e2/attachment-0001.sig>


More information about the libvir-list mailing list