[libvirt-users] Live migration process in src/qemu_driver.ca

[Faizul Bari]

Thanks Eric.

So, I need to look at QEMU. Do you know which files/functions should I look
at?

​--
Faiz​


On Thu, Mar 20, 2014 at 12:41 PM, Eric Blake <eblake at redhat.com> wrote:

> On 03/20/2014 10:05 AM, Faizul Bari wrote:
> > ​Hello,
> >
> > I have been trying to track different phases of a live migration
> process. I
> > am using libvirt ​with qemu-kvm. I am issuing migration commands using
> > virsh.
> >
> > Now, I want to measure the time spent in each phase of live migration,
> > e.g., pre-copy and stop-copy. I stumbled upon the file qemu_driver.c. It
> > has functions like
> >
> > qemudDomainMigratePrepare2
> > qemudDomainMigratePerform
> > qemudDomainMigrateFinish2
>
> These functions perform different handshakes between the two libvirt
> ends of the migration.  However, the entire migration is done by a
> single qemu monitor command, and it is that monitor command that further
> divides the work into phases such as pre-copy and stop-copy.
>
> >
> > I want to know whether qemudDomainMigratePerform and
> > qemudDomainMigrateFinish2 directly map to the pre-copy and stop-copy
> phase?
> > or the qemudDomainMigratePerform function performs both of them?
>
> The MigratePerform function is the one place that calls the qemu monitor
> command.  I know there have been proposals upstream in qemu to add
> additional statistics in 'query-migrate' monitor command; perhaps there
> is still more work needed in libvirt to grab those additional statistics
> in a manner that can be exposed to the user.
>
> --
> Eric Blake   eblake redhat com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>
>
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