Re: [Qemu-devel] [PATCH 4/6] dirty-bitmaps: clean-up bitmaps loading and migration logic

[Denis V. Lunev]

On 08/02/2018 12:50 PM, Dr. David Alan Gilbert wrote:
> * Denis V. Lunev (address@hidden) wrote:
>
>
>>> I don't quite understand the last two paragraphs.
>> we are thinking right now to eliminate delay on regular IO
>> for migration. There is some thoughts and internal work in
>> progress. That is why I am worrying.
> What downtime are you typicaly seeing and what are you aiming for?
>
> It would be good if you could explain what you're planning to
> fix there so we can get a feel for it nearer the start of it
> rather than at the end of the reviewing!
>
> Dave
The ultimate goal is to reliable reach 100 ms with ongoing IO and
you are perfectly correct about reviewing :)

Though the problem is that right now we are just trying to
invent something suitable :(

Den

>>> However, coming back to my question; it was really saying that
>>> normal guest IO during the end of the migration will cause
>>> a delay; I'm expecting that to be fairly unrelated to the size
>>> of the disk; more to do with workload; so I guess in your case
>>> the worry is the case of big large disks giving big large
>>> bitmaps.
>> exactly!
>>
>> Den
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK