Re: [Qemu-block] [PATCH 5/9] mirror: improve performance of mirroring of empty disk

[Eric Blake]

On 06/14/2016 09:25 AM, Denis V. Lunev wrote:
> We should not take into account zero blocks for delay calculations.
> They are not read and thus IO throttling is not required. In the
> other case VM migration with 16 Tb QCOW2 disk with 4 Gb of data takes
> days.
> 
> Signed-off-by: Denis V. Lunev <address@hidden>
> Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> CC: Stefan Hajnoczi <address@hidden>
> CC: Fam Zheng <address@hidden>
> CC: Kevin Wolf <address@hidden>
> CC: Max Reitz <address@hidden>
> CC: Jeff Cody <address@hidden>
> CC: Eric Blake <address@hidden>
> ---
>  block/mirror.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)

Seems reasonable, but I'll let others more familiar with throttling give
the final say.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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