Re: [libvirt-users] Sluggish performance with virtio and Win10

John Obaterspok
Fri, 19 Feb 2016 06:16:12 -0000

2016-02-18 15:15 GMT+01:00 Martin Kletzander <mkletzan@redhat.com>:

> On Thu, Feb 18, 2016 at 12:59:52PM +0100, John Obaterspok wrote:
>
>> 2016-02-18 11:25 GMT+01:00 Martin Kletzander
<mkletzan@redhat.com>:
>>
>> On Thu, Feb 18, 2016 at 10:41:42AM +0100, John Obaterspok wrote:
>>>
>>> 2016-02-18 10:13 GMT+01:00 Martin Kletzander
<mkletzan@redhat.com>:
>>>>
>>>> On Thu, Feb 18, 2016 at 08:49:38AM +0100, John Obaterspok
wrote:
>>>>
>>>>>
>>>>> Hello,
>>>>>
>>>>>>
>>>>>> I'm using virt-manager on my F23 box to run a
Windows 10 image but the
>>>>>> performance is so bad it's killing me.
>>>>>>
>>>>>> I have "vmx" flag in /proc/cpuinfo
>>>>>>
>>>>>> # lsmod |grep kvm
>>>>>> kvm_intel             167936  6
>>>>>> kvm                   503808  1 kvm_intel
>>>>>>
>>>>>> virtio-win-0.1.112-1.noarch
>>>>>>
>>>>>> But no virtio modules loaded. Should they be loaded
nowadays?
>>>>>>
>>>>>>
>>>>>> Not on the host AFAIK.
>>>>>
>>>>> The disk format used is vmdk with no caching and native
mode.
>>>>>
>>>>> The io is 100% in windows task manager performing less than
1MB/s
>>>>>>
>>>>>> Any clues?
>>>>>>
>>>>>>
>>>>>> What are the figures from the host?  What is qemu doing
and what are
>>>>>> the
>>>>>>
>>>>> other processes and devices doing?
>>>>>
>>>>>
>>>>> What is the best way to find this out?
>>>>>
>>>>
>>>>
>>>> {,a,h}top should do for the initial runs, just to see if the
block layer
>>> is busy or the CPU is busy or something else is blocking it
>>>
>>>
>>> atop seems to indicate that sdd is busy?
>>
>> DSK |          sdd |  busy     96% |              |  read    1455 |
write
>> 1319 |  KiB/r      5 | KiB/w      9 |               | MBr/s   0.74 |
MBw/s
>>  1.26  | avq     1.01 |               | avio 3.43 ms |
>>
>> # mount | grep sdd
>> /dev/sdd2 on /vm type ext4 (rw,relatime,seclabel,data=ordered)
>>
>>
> And it doesn't do that in any other process on the host?  It looks like
> it's not related to virtualisation...
>
>
Hi,

I changed from vmdk to raw and the Write performance went from 1.6 MB/s to
~100 MB/s
Is vmdk write performance so bad?

Result:
http://postimg.org/image/gcqe5affn/

-- john