[libvirt-users] Sluggish performance with virtio and Win10

[Martin Kletzander]

On Thu, Feb 18, 2016 at 12:59:52PM +0100, John Obaterspok wrote:
>2016-02-18 11:25 GMT+01:00 Martin Kletzander <mkletzan at 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 at 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...

>
>guest configuration is below:
>
><domain type='kvm'>
>  <name>win10-box</name>
>  <uuid>d4a67adb-5d30-42f8-b8c6-d3c4598700f2</uuid>
>  <memory unit='KiB'>4194304</memory>
>  <currentMemory unit='KiB'>4194304</currentMemory>
>  <vcpu placement='static'>4</vcpu>
>  <os>
>    <type arch='x86_64' machine='pc-i440fx-2.4'>hvm</type>
>  </os>
>  <features>
>    <acpi/>
>    <apic/>
>    <pae/>
>    <hyperv>
>      <relaxed state='on'/>
>      <vapic state='on'/>
>      <spinlocks state='on' retries='8191'/>
>    </hyperv>
>    <kvm>
>      <hidden state='on'/>
>    </kvm>
>    <vmport state='off'/>
>  </features>
>  <cpu mode='host-model'>
>    <model fallback='allow'/>
>  </cpu>
>  <clock offset='localtime'>
>    <timer name='rtc' tickpolicy='catchup'/>
>    <timer name='pit' tickpolicy='delay'/>
>    <timer name='hpet' present='no'/>
>    <timer name='hypervclock' present='yes'/>
>  </clock>
>  <on_poweroff>destroy</on_poweroff>
>  <on_reboot>restart</on_reboot>
>  <on_crash>restart</on_crash>
>  <pm>
>    <suspend-to-mem enabled='no'/>
>    <suspend-to-disk enabled='no'/>
>  </pm>
>  <devices>
>    <emulator>/usr/bin/qemu-kvm</emulator>
>    <disk type='file' device='cdrom'>
>      <driver name='qemu' type='raw'/>
>      <source file='/usr/share/virtio-win/virtio-win.iso'/>
>      <target dev='hda' bus='ide'/>
>      <readonly/>
>      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
>    </disk>
>    <disk type='file' device='disk'>
>      <driver name='qemu' type='vmdk' cache='none' io='native'/>
>      <source file='/vm/storage/win10-box.img'/>
>      <target dev='vda' bus='virtio'/>
>      <boot order='1'/>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x0a'
>function='0x0'/>
>    </disk>
>    <controller type='usb' index='0' model='ich9-ehci1'>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
>function='0x7'/>
>    </controller>
>    <controller type='usb' index='0' model='ich9-uhci1'>
>      <master startport='0'/>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
>function='0x0' multifunction='on'/>
>    </controller>
>    <controller type='usb' index='0' model='ich9-uhci2'>
>      <master startport='2'/>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
>function='0x1'/>
>    </controller>
>    <controller type='usb' index='0' model='ich9-uhci3'>
>      <master startport='4'/>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
>function='0x2'/>
>    </controller>
>    <controller type='pci' index='0' model='pci-root'/>
>    <controller type='ide' index='0'>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x01'
>function='0x1'/>
>    </controller>
>    <controller type='virtio-serial' index='0'>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x05'
>function='0x0'/>
>    </controller>
>    <controller type='sata' index='0'>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x08'
>function='0x0'/>
>    </controller>
>    <interface type='direct'>
>      <mac address='52:54:00:cc:f0:31'/>
>      <source dev='eno1' mode='bridge'/>
>      <model type='virtio'/>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x03'
>function='0x0'/>
>    </interface>
>    <serial type='pty'>
>      <target port='0'/>
>    </serial>
>    <console type='pty'>
>      <target type='serial' port='0'/>
>    </console>
>    <input type='tablet' bus='usb'/>
>    <input type='mouse' bus='ps2'/>
>    <input type='keyboard' bus='ps2'/>
>    <graphics type='spice' autoport='yes'/>
>    <sound model='ich6'>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x04'
>function='0x0'/>
>    </sound>
>    <video>
>      <model type='vga' vram='16384' heads='1'/>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x02'
>function='0x0'/>
>    </video>
>    <memballoon model='virtio'>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x07'
>function='0x0'/>
>    </memballoon>
>  </devices>
></domain>
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