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

[Orit Wasserman]

On 03/04/2013 07:10 PM, Peter Lieven wrote:
> 
> Am 01.03.2013 um 17:04 schrieb Eric Blake <address@hidden>:
> 
>> 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.
> 
> At least for the artificially generated load.
> 
> @Paolo: Have you seen my other question? Can the same page be transferred in 
> the same round
> more than once? If yes, I have to improve the patch for that case.
The same page can't be transferred more than once in the same round.

Orit
> 
> Peter
>