Re: [Qemu-devel] [PATCH V4 01/10] NUMA: Support multiple CPU ranges on -numa option

[Wanlong Gao]

On 07/09/2013 03:25 AM, Anthony Liguori wrote:
> Eric Blake <address@hidden> writes:
> 
>> On 07/05/2013 12:41 PM, Eduardo Habkost wrote:
>>> On Thu, Jul 04, 2013 at 05:53:08PM +0800, Wanlong Gao wrote:
>>>> From: Bandan Das <address@hidden>
>>>>
>>>> This allows us to use the "cpus" property multiple times
>>>> to specify multiple cpu (ranges) to the -numa option :
>>>>
>>>> -numa node,cpus=1,cpus=2,cpus=4
>>>> or
>>>> -numa node,cpus=1-3,cpus=5
>>>>
>>>> Note that after this patch, the defalut suffix of "-numa node,mem=N"
>>>> will no longer be "M". So we must add the suffix "M" like "-numa 
>>>> node,mem=NM"
>>>> when assigning "N MB" of node memory size.
>>>
>>> Such an incompatible change is not acceptable, as it would break
>>> existing configurations. libvirt doesn't specify any suffix and expects
>>> it to always mean "MB".
>>
>> Newer libvirt can be taught to append 'M' when it detects it is talking
>> to newer qemu.  While you have a point that it is annoying to force
>> users to upgrade to a newer libvirt merely because they upgraded qemu,
>> the libvirt point of view is that the following are supported:
>>
>> old libvirt -> old qemu
>> new libvirt -> old qemu
>> new libvirt -> new qemu
>>
>> but that this combination is always best effort and not required to work:
>>
>> old libvirt -> new qemu
> 
> That's fine for libvirt, but we don't break command line compatibility
> in QEMU.  So this patch needs to change.

But if we follow Paolo's suggestion like:
    -numa node,nodeid=0,cpus=0 -numa node,nodeid=1,cpus=1 \
    -numa mem,nodeid=0,size=1G,policy=membind,hostnode=0-1
    -numa mem,nodeid=1,size=2G,policy=interleave,hostnode=1

We already break the command line compatibility.
Why not change it be a really "size" options without default suffix?

Thanks,
Wanlong Gao

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