[libvirt] [PATCH v2] libvirt support to force convergence of live guest migration

Jim Fehlig jfehlig at suse.com
Tue Feb 25 04:33:28 UTC 2014


Chegu Vinod wrote:
> Hello,
> 'am sending this updated patch as an attachment (as I was having some
> issues with my smtp server and git send-email setup).
> Thanks,
> Vinod
>
> Subject: [PATCH v2] libvirt support to force convergence of live guest migration
>
> Changes since RFC (i.e. v1) patch :
> - Incorporated feedback from Jiri Denemark
>   

Looks like you addressed all of Jiri's comments from V1, except for the
name of the VIR_MIGRATE_AUTO_CONVERGE flag.  But I don't have a better
suggestion either.

> 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 may NOT converge.
>
> Recently support was added in qemu (version 1.6) to allow a user to
> choose if they wish to force convergence of their migration via a
> new migration capability : "auto-converge". This feature allows for qemu
> to auto-detect lack of convergence and trigger a throttle-down of the
> VCPUs.
>
> This patch includes the libvirt support needed to trigger this
> feature. (Testing is in progress)
>
> Signed-off-by:  Chegu Vinod <chegu_vinod at hp.com>
> ---
>  include/libvirt/libvirt.h.in |  1 +
>  src/qemu/qemu_migration.c    | 40 ++++++++++++++++++++++++++++++++++++++++
>  src/qemu/qemu_migration.h    |  3 ++-
>  src/qemu/qemu_monitor.c      |  2 +-
>  src/qemu/qemu_monitor.h      |  1 +
>  tools/virsh-domain.c         |  7 +++++++
>   

As mentioned earlier, this needs documented in virsh.pod, similar to the
virsh.pod changes Jiri made when introducing the VIR_MIGRATE_COMPRESSED
flag in commit ecfff1da.

Regards,
Jim




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