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Subject: Re: [Qemu-devel] [question] the patch which affect performance of
	virtio-scsi
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To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel <qemu-devel@nongnu.org>



On 2015-2-8 18:10, Paolo Bonzini wrote:
> 
> 
> On 07/02/2015 12:26, Wangting (Kathy) wrote:
>> OK, Thank you very much for your detailed explanation.
>>
>> But I have another question about the big change from qemu-1.5.3 to qemu-1.6.0-rc0.
>>
>> When I use ramdisk for IO performance testing, the result is as follows.
>>
>> [fio-test]          rw         bs         iodepth    jobs       bw         iops
>> ------------------------------------------------------------------------------------
>> qemu-1.5.3          read       4k         32          1         285MB/s    73208
>> qemu-1.6.0-rc0      read       4k         32          1         253MB/s    64967
>>
>> And virtio-blk is the same.
>>
>> I know there are so many differences between qemu-1.5 and qemu-1.6, but I am confused about
>> what new features impact the performance so much. Do you know it?
> 
> No, sorry.  Please try newer versions first and see if this was fixed.
> QEMU 1.6 is more than a year old.
> 
> Paolo
> 
> 

OK, thanks.

Ting