Re: [Qemu-devel] [PATCH] migration: use XBZRLE only after bulk stage

[Eric Blake <eblake@redhat.com>]

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On 03/01/2013 07:50 AM, Peter Lieven wrote:

> just a quick test on my desktop:
> 
> ~/git/qemu$ x86_64-softmmu/qemu-system-x86_64 -k de -enable-kvm -m 1024
> -drive
> if=virtio,file=iscsi://172.21.200.31/iqn.2001-05.com.equallogic:0-8a0906-16470e107-713001aa6de511e0-001-test/0
> -vnc :1 -boot dc -monitor stdio
> 
> using ubuntu 12.04.1 desktop and the example from docs/xbzrle.txt

Thanks.  Reformatting a bit:

> 
> a) with the patch

designated with '+'

> b) without the patch

designated with '-'

+ total time: 22185 milliseconds
- total time: 22410 milliseconds

Shaved 0.3 seconds, better than 1%!

+ downtime: 29 milliseconds
- downtime: 21 milliseconds

Not sure why downtime seemed worse, but probably not the end of the world.

+ transferred ram: 706034 kbytes
- transferred ram: 721318 kbytes

Fewer bytes sent - good.

+ remaining ram: 0 kbytes
- remaining ram: 0 kbytes
+ total ram: 1057216 kbytes
- total ram: 1057216 kbytes
+ duplicate: 108556 pages
- duplicate: 105553 pages
+ normal: 175146 pages
- normal: 179589 pages
+ normal bytes: 700584 kbytes
- normal bytes: 718356 kbytes

Fewer normal bytes...

+ cache size: 67108864 bytes
- cache size: 67108864 bytes
+ xbzrle transferred: 3127 kbytes
- xbzrle transferred: 630 kbytes

...and more compressed pages sent - good.

+ xbzrle pages: 117811 pages
- xbzrle pages: 21527 pages
+ xbzrle cache miss: 18750
- xbzrle cache miss: 179589

And very good improvement on the cache miss rate.

+ xbzrle overflow : 0
- xbzrle overflow : 0

Thanks, this proves it's a good patch.

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


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