Re: [Qemu-devel] [PATCHv2] block: introduce BDRV_O_SEQUENTIAL

[Peter Lieven]

Am 28.03.2014 um 11:02 schrieb Peter Lieven <address@hidden>:

> On 21.03.2014 13:06, Paolo Bonzini wrote:
>> Il 21/03/2014 12:49, Peter Lieven ha scritto:
>>> A 10G logical volume was created and filled with random data.
>>> Then the logical volume was exported via qemu-img convert to an iscsi 
>>> target.
>>> Before the export was started all caches of the linux kernel where dropped.
>>> 
>>> Old behavior:
>>> - The convert process took 3m45s and the buffer cache grew up to 9.67 GB 
>>> close
>>>   to the end of the conversion. After qemu-img terminated all the buffers 
>>> were
>>>   freed by the kernel.
>>> 
>>> New behavior with the -N switch:
>>> - The convert process took 3m43s and the buffer cache grew up to 15.48 MB 
>>> close
>>>   to the end with some small peaks up to 30 MB durine the conversion.
>>> 
>>> Signed-off-by: Peter Lieven <address@hidden>
>>> ---
>>> v1->v2: - added test example to commit msg
>>>        - added -N knob to qemu-img
>> 
>> I'm sorry, I cannot find the original discussion.  Why is the new knob 
>> needed?
> 

Is there any more info needed or modifications wanted?

Thanks,
Peter