[libvirt] """virsh schedinfo [--weight number] domain""" doesn't work with virsh(libxl) for managing Xen domains.

[Jim Fehlig]

On 09/27/2016 03:27 AM, Volo M. wrote:
> Hi Devs,
>
> We're using Centos 7 Xen hypervisors and try to use Libvirt(libxl) for
> managing Xen guest domains.
> We noticed that we can't set cpu weight values for Xen domains with libvirt
> (tested for libvirt v.1.3 and v.2.2) even though its possible to do with XL
> toolkit.
> [root at hv1xen ~]# virsh schedinfo --domain rtp6a88apsm3or --cap=5
> Scheduler      : credit
> weight         : 1000
> [root at hv1xen ~]# virsh schedinfo --domain rtp6a88apsm3or --weight=50
> Scheduler      : credit
> error: invalid scheduler option: weight

Thanks for the report. That is a bug in the libvirt libxl driver. I've sent a
patch to fix it

https://www.redhat.com/archives/libvir-list/2016-September/msg01284.html

>
> We noticed in documentation for 'virsh' like  this
> https://linux.die.net/man/1/virsh that the cpu weight option is going to be
> deprecated:
> *"""Note*: The weight and cap parameters are defined only for the XEN_CREDIT
> scheduler and are now /DEPRECATED/ . """

That "note" is bogus and was incorrectly introduced all the way back in Oct 2008
via commit 6c504d6a. Even today, the default scheduler in Xen is credit and it
supports setting cap and weight. I'll send a doc patch to remove the "and are
now deprecated".

Regards,
Jim