Re: [Qemu-devel] [PATCH v4 00/10] cpu: add device_add foo-x86_64-cpu support

[Chen Fan <chen.fan.fnst@cn.fujitsu.com>]

On 02/26/2015 05:35 PM, Andreas Färber wrote:
> Hi,
>
> Am 25.02.2015 um 10:58 schrieb Chen Fan:
>> On 02/25/2015 12:56 AM, Andreas Färber wrote:
>>> Am 24.02.2015 um 02:25 schrieb Gu Zheng:
>>>> The issues you commented in the previous version have been fixed in
>>>> this one.
>>> What I have repeatedly rejected is "device_add foo-x86_64-cpu". This is
>>> still in 00/10 and 09/10. Most of the actual changes however do look to
>>> be going in the right direction of making 'realize' work as expected for
>>> foo-x86_64-cpu.
>>>
>>> As for the socket-based device_add I mentioned, I had pushed a work
>>> branch qom-cpu-x86 and had some off-list discussions for some of the
>>> other architectures but did not submit it as an RFC yet. What I am still
>>> working on is dynamic properties to allocate cores (threads TBD) for
>>> "device_add x86_64-cpu-socket,cores=n".
>> Can you explain all your thoughts about cpu hotplug feature with
>> socket-based,
>> or how goals do you want to see?
> Basically I am implementing Anthony's suggestion from a year or two
> back, that is moving towards using real building blocks such as
> Xeon-E5-4242 as shortcut for a 6-core, 2-HT device, ultimately replacing
> -cpu. Think of what can be plugged in real servers - a socket is atomic
> in reality, you can't add cores or hyperthreads dynamically. And the QOM
> realize model then forces me to use child<> properties inside the socket
> object for consistent recursive processing.
yes, I agree with you.

but the existed command 'cpu-add' is adding one logic processor each time.
it will cause compatibility with the socket-based cpu device. and what
do you think to solve this problem ?

Thanks,
Chen

>
> Regards,
> Andreas
>
>> and what is the status of "device_add x86_64-cpu-socket" ?
>>
>> after that, I think we can do somethings to help you to achieve your ideas.
>>
>> Thanks,
>> Chen
>>
>>>> Could you please help to review it?
>>> Will get to it Friday earliest.
>>>
>>> Regards,
>>> Andreas
>>>
>