Re: [Qemu-devel] [PATCH v3] Throttle-down guest when live migration does not converge.

[Chegu Vinod <chegu_vinod@hp.com>]

On 5/1/2013 5:38 AM, Eric Blake wrote:
> On 05/01/2013 06:22 AM, Chegu Vinod wrote:
>> Busy enterprise workloads hosted on large sized VM's tend to dirty
>> memory faster than the transfer rate achieved via live guest migration.
>> Despite some good recent improvements (& using dedicated 10Gig NICs
>> between hosts) the live migration does NOT converge.
>> ---
>>
>> Changes from v2:
>> - incorporated feedback from Orit, Juan and Eric
>> - stop the throttling thread at the start of stage 3
>> - rebased to latest qemu.git
>>
>> +++ b/qapi-schema.json
>> @@ -600,9 +600,14 @@
>>   #          loads, by sending compressed difference of the pages
>>   #
>>   # Since: 1.2
>> +#
>> +# @auto-converge: Migration supports automatic throttling down of guest
>> +#          to force convergence. Disabled by default.
>> +#
>> +# Since: 1.6
>>   ##
> I've already argued that ALL new migration capabilities should be
> disabled by default (see the thread on 'x-rdma-pin-all', which will be a
> merge conflict if it gets applied before your patch).  So I don't think
> that last sentence adds anything, and can be dropped.
>
> I think this works, although it's the first instance of having two
> top-level Since: tags on a single JSON entity.  I was envisioning:
>
> @xbzrle: yadda... pages
>
> @auto-convert: Migration supports... convergence (since 1.6)
>
> Since: 1.2
>
> to match the conventions elsewhere that the overall JSON entity (the
> enum MigrationCapability) exists since 1.2, but the addition of
> auto-convert happened in 1.6.
>
> However, as nothing parses the .json file to turn it into formal docs
> (yet), I'm not going to insist on a respin if this is the only problem
> with your patch.  I'm not comfortable enough with my skills in reviewing
> the rest of the patch, or I'd offer a reviewed-by.
>
I shall make the suggested changes.
Appreciate your review feedback on this part of the change.

Thanks
Vinod