[libvirt] [RFC] libvirt support multi-thread compression for live migration

[Qiao,Liyong]

On 2015年06月04日 20:09, Jiri Denemark wrote:
> On Tue, Jun 02, 2015 at 11:02:27 -0600, Eric Blake wrote:
>> On 06/02/2015 07:56 AM, Qiao, Liyong wrote:
>>> Hi Eric
>>> Thanks for replying the mail, replied in lines.
>>>
>>>> +virdomainMigrateGetParameters(virDomainPtr domain,
>>>> +                                  int *level,
>>>> +                                  int *threads,
>>>> +                                  int *dthreads,
>>>> +                                  int flags)
>>>> +
>>> I'd rather we used virTypedParameters, to make it easier to use the same API to pass ALL future possible tuning parameters, rather than just hard-coding to only the parameters of this one feature.
>>>
>>> Okay ,that sound good, but if virTypedParameters can be passed to qemu_driver such as qemu_monitor_json.c qemu_monitor_text.c ?
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>>
>> Use existing API for a guide - for example, virDomainSetBlockIoTune
>> takes virTypedParamters, as well as defines a specific set of parameters
>> that it will understand.
> And do we actually need to changed these migration parameters on the fly
> when migration is already running. I can imagine we would need to do so
> for some parameters but multithreaded compression sounds like something
> that needs to be configured when migration starts and there's nothing to
> be tuned on the fly. If this is the case, I think we should just add
> these new parameters to virDomainMigrate3 instead of requiring another
> API to be called to actually configure multithreaded compression.
>
> The separate API makes it a bit harder to repeat migration (which
> previously failed) with a different parameters (e.g., without
> multithreaded compression).
hi jirka
thanks for your advice, that make sense for me.

if I understanding you correctly,
then we need only do this

virsh migrate --live --compressed --compress-level 1--compress-threads 8 
--decompress-threads 2

and all compressed parameters (compress-level ,compress-threads, 
decompress-threads)  only
be specified when we do call virDomainMigrate3 instead of expose to user 
by 'virsh migrate-setparameters' ?

I think that's good for me, and make user easy to start LM.

thanks,
Eli.

> Jirka

-- 
BR, Eli(Li Yong)Qiao

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