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Re: [Qemu-devel] question about performance of dataplane
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] question about performance of dataplane |
Date: |
Sun, 07 Apr 2013 09:05:47 -0500 |
User-agent: |
Notmuch/0.13.2+93~ged93d79 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) |
Zhangleiqiang <address@hidden> writes:
> Hi, Stefan:
>
> I have done some testing to compare the performance of dataplane and
> non-dataplane. But the result did not meet my expectations, the performance
> of disk with dataplane enabled did not have advantage over non-dataplane.
>
> The following contains the environment info and testing results.
> Does my testing method or testing environment have something wrong ? Could
> you give me some advice? I can provide more information if need.
>
>
> 1. Environment:
> a). Qemu 1.4 master branch
> b). kernel: 3.5.0-2.fc17.x86_64
> c). virtual disks location: the same local SATA harddisk
> with ext4 fs
I doubt you'll see any performance difference with a single SATA drive.
There's no real parallelism possible as you have exactly one spindle
available.
> datasize/RW_Ratio IOPS_dataplane IOPS_non_dataplane
> MBPS_dataplane MBPS_non_dataplane
> 16K/0% 294.094948 293.609606
> 4.595234 4.58765
> 16K/25% 283.096745 281.649258
> 4.423387 4.40077
> 16K/75% 316.039801 309.585336
> 4.938122 4.837271
> 32K/0% 257.529537 258.806128
> 8.047798 8.087692
> 32K/25% 253.729281 253.756673
> 7.92904 7.929896
> 32K/75% 292.384568 280.991434
> 9.137018 8.780982
> 4K/0% 321.599352 324.116063
> 1.256247 1.266078
> 4K/25% 309.906635 309.294278
> 1.210573 1.208181
> 4K/75% 350.168882
> 350.772329 1.367847
> 1.370204
You are getting 300 MB/s to a single SATA disk? I strongly suspect
you are seeing cache interaction. I'd suggest disabling WCE on the disk
if you're going to benchmark like this.
I'd also guess 300 MB/s is what you're maxing out at with native too.
So presumably normal virtio-blk is already getting close to native
performance. dataplane certainly isn't going to give you better than
native performance :-)
Regards,
Anthony Liguori
>
>
>
> ----------
> Leiqzhang
>
> Best Regards
>
>
>> 发件人: address@hidden [mailto:address@hidden 代表 leiqzhang
>> 发送时间: 2013年3月28日 12:03
>> 收件人: Stefan Hajnoczi
>> 抄送: address@hidden; address@hidden; address@hidden; 张 磊强
>> 主题: [Qemu-devel] 回复: dataplane bug: fail to start Windows VM with dataplane
>> enable
>>
>> Hi, Stefan:
>>
>> Thank for your reply and patch. I have done the test for Windows 7,
>> Windows 2003, and fedora.
>>
>> The patch has fixed the problem now, thanks.
>>
>> --
>> leiqzhang
>> Sent by Sparrow
>>
>> 在 2013年3月27日星期三,23:41,Stefan Hajnoczi 写道:
>> On Tue, Mar 26, 2013 at 11:10:35PM +0800, 张磊强 wrote:
>> Hi, Paolo && Stefan:
>>
>> When I test the dataplane feature with qemu master, I find that
>> Windows (Windows 7 and Windows 2003) VM will hang if dataplane is
>> enabled. But if I try to start a Fedora VM, it can start normally.
>>
>> The command I boot QEMU is:
>> x86_64-softmmu/qemu-system-x86_64 -enable-kvm -m 1024 -smp 2 -drive
>> file=win7.img,if=none,id=drive-virtio-disk,format=raw,cache=none,aio=native
>> -device
>> virtio-blk-pci,config-wce=off,scsi=off,x-data-plane=on,drive=drive-virtio-disk,id=virtio-disk
>>
>> I found the similar bug has reported some days ago:
>> http://lists.nongnu.org/archive/html/qemu-devel/2013-03/msg02200.html
>> . And a patch for this bug has already committed by Paolo at Mar 13:
>> http://lists.nongnu.org/archive/html/qemu-devel/2013-03/msg02200.html
>> .
>>
>> But it cannot work under my environment. Could you give me some advise
>> to debug this problem ? I can provide more information if need.
>>
>> I sent a fix and CCed you on the patch. Please test it if you have
>> time.
>>
>> Stefan
>>
- Re: [Qemu-devel] 答复: question about perfor mance of dataplane, (continued)
- Re: [Qemu-devel] 答复: question about perfor mance of dataplane, Stefan Hajnoczi, 2013/04/04
- [Qemu-devel] 答复: 答复: question about pe rformance of dataplane, Zhangleiqiang, 2013/04/07
- Re: [Qemu-devel] 答复: 答复: question about pe rformance of dataplane, Abel Gordon, 2013/04/07
- [Qemu-devel] 答复: 答复: 答复: question a bout performance of dataplane, Zhangleiqiang, 2013/04/07
- Re: [Qemu-devel] 答复: 答复: 答复: question a bout performance of dataplane, Abel Gordon, 2013/04/07
- Message not available
- Re: [Qemu-devel] 答复: 答复: 答复: question abo ut performance of dataplane, Abel Gordon, 2013/04/07
- [Qemu-devel] 答复: 答复: 答复: 答复: quest ion about performance of dataplane, Zhangleiqiang, 2013/04/08
- Re: [Qemu-devel] 答复: 答复: 答复: 答复: quest ion about performance of dataplane, Abel Gordon, 2013/04/08
- Re: [Qemu-devel] 答复: 答复: 答复: 答复: quest ion about performance of dataplane, Zhangleiqiang, 2013/04/08
- Re: [Qemu-devel] 答复: 答复: 答复: 答复: quest ion about performance of dataplane, Abel Gordon, 2013/04/08
Re: [Qemu-devel] question about performance of dataplane,
Anthony Liguori <=