Re: [Qemu-devel] [RFC][PATCH 10/16 v6] run dump at the background

[Jan Kiszka]

On 2012-02-15 04:47, Wen Congyang wrote:
> At 02/15/2012 02:27 AM, Jan Kiszka Wrote:
>> On 2012-02-14 19:05, Jan Kiszka wrote:
>>> On 2012-02-09 04:28, Wen Congyang wrote:
>>>> The new monitor command dump may take long time to finish. So we need run 
>>>> it
>>>> at the background.
>>>
>>> How does it work? Like live migration, i.e. you retransmit (overwrite)
>>> already written but then dirtied pages? Hmm... no.
>>>
>>> What does background mean then? What is the use case? What if the user
>>> decides to resume the vm?
>>
>> OK, that is addressed in patch 15! I would suggest merging it into this
>> patch. It makes sense to handle that case gracefully right from the
>> beginning.
> 
> OK, I will merge it.
> 
>>
>> OK, now I have some other question: What is the point of rate-limiting
>> the dump? The guest is not running, thus not competing for bandwidth.
> 
> I use bandwidth to try to control the writing speed. If we write the vmcore
> to disk in a high speed, it may affect some other appilications which use
> the same disk too.

Just like the guest of that particular VM can do. I don't think we need
this level of control here, it will be provided (if required) at a
different level, affecting the whole QEMU process. Removing the vmcore
bandwidth control will simplify code and user interface.

Jan

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