[libvirt] qemu -numa option and non-contiguous CPU ranges

[Andre Przywara]

On 06/21/2012 07:51 PM, Eduardo Habkost wrote:
> Hi,
>
> I just noticed libvirt tries to use the -numa option in a way that qemu
> never understood: if a node is configured to have a non-contiguous set
> of CPUs, it tries to generate a command-line option that looks like:
>
> "-numa node,nodeid=...,cpus=0,2,4,mem=..."
>                              ^^^^^
>
> But this format was never supported by qemu. This format is even a bit
> weird, as "," is an option separator, and it is being used as a
> separator _inside_ an option.

Exactly this was the reason back then to not support non-contiguous set 
of CPUs. Inside qemu there is no reason why this shouldn't work, it was 
just hard to write on the command line. So after a short discussion we 
decided to drop this for the time being. If you have a great idea how to 
specify this (I think a comma will not work, because it will be catched 
earlier), I am all ears.

Regards,
Andre.

> My question is: should we support this option format in qemu, or should
> we change libvirt to use another format (that has yet to be implemented,
> because currently there's no way to specify a non-contiguous set of CPUs
> for a NUMA node).
>
> Any suggestions?
>


-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany