Degraded performance with Windows 2008 R2 with applications

[Mathias Klette <mklette@gmail.com>]

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Hi list,

I'm not sure if this is the right list, but I have to ask for help on
some performance issues with KVM and Windows 2008 R2.

Windows guest is working properly on a clean install. But once some
applications get installed - especially MSSQL, but others as well -
system becomes pretty unresponsive. In turns, a login to the system can
take several minutes, context menus are opened badly slow and the clock
is not updated correctly which leads to differences of whole hours after
only some few hours uptime. Verifying with performance monitor in
Windows I could only see load on disk IO, not on CPU, memory. From
kvm/qemu point of view: A raw-image stored on a ext4 formatted LVM
volume is used and started with following configurations via libvirt -
see attached.

On the host system runs Debian Squeeze with a custom 2.6.38-rc2-amd64
kernel. Packages kvm, qemu-kvm and qemu-utils have been re-packaged from
source with only slight changes from original Debian source. Versions
following

linux-source-2.6.38-rc2-amd64 (custom kernel)
kvm                                                      1:0.13.60-1
qemu                                                     0.12.5+dfsg-3
qemu-keymaps                                             0.12.5+dfsg-3
qemu-kvm                                                 0.13.60-1.2
qemu-system                                              0.12.5+dfsg-3
qemu-user                                                0.12.5+dfsg-3
qemu-user-static                                         0.12.5+dfsg-3
qemu-utils                                               0.13.60-4
libvirt-bin                                              0.8.6-1
libvirt0                                                 0.8.6-1

I've tested with iozone to compare IO with a linux guest and also to
verify changes made to improve situation - but nothing really helped.

TESTS with "iozone -s 4G -r 256k -c -e":
                                                              random
random    bkwd   record   stride
                KB  reclen   write rewrite    read    reread    read
write    read  rewrite     read   fwrite frewrite   fread  freread

disc: host, host fs: ext4
           4194304     256  212213  219411  1770921  1778980 1772993
222316 1251443  2427416  1556529   211803   225559 2028445  2033889

disc: host, host fs: ext4, mntopt:
noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr
           4194304     256  458299  497838  2130939  1981932 1980227
511864 1810650  2556598  1838972   459005   467800 1572550  1576777

guest: debian squeeze, disc type: raw, cache: writeback, host fs: ext3
           4194304     256  111340   82813    81190    97227  116749
128444  378383  2384227    79760   170192   117359   88191    96565

guest: windows 2008 r2. disc type: raw, cache: writeback, host fs: ext4
           4194304     256   67787   27191    18102    38490   57438
96373   44393  3331227    56250    39590    35381   38925    59479

guest: windows 2008 r2, disc type: raw, cache: writeback, host fs: ext4,
mntopts (see above), guest: win 2008 r2, 2 CPU => 4 CPU, 2G => 8G RAM
           4194304     256   25542   55815  675272    634422  655875
34512 1022106  2880516   220929    25342    34893  574888   549021

guest: windows 2008 r2, disc type: raw, cache: writeback, host fs: ext4,
mntopts (see above), guest: win 2008 r2, 2 CPU => 4 CPU, 2G => 8G RAM,
disabled apps:
           4194304     256   23842   27387  665746    737001   85355
30551  993698  2966299    67414    27245    29198   83649   575503
           4194304     256   23832   25542  662877     85437  652512
30592  840599  3201253    65488    27701    21907  585014   565069
           4194304     256   18492   37256   86426    716990  659070
33134  988579  2929210   206683    27324    21285  640326   632402

So, now the questions are: Are any issues known, especially regards
Windows 2008 R2 or hints on further enhancements possible to kvm for
usage with Windows host systems?

Mathias

[-- Attachment #2: xml --]
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<domain type='kvm'>
  <name>VM-34</name>
  <memory>4194304</memory>
  <currentMemory>4194304</currentMemory>
  <vcpu>4</vcpu>
  <os>
    <type arch='x86_64' machine='pc-0.12'>hvm</type>
    <boot dev='cdrom'/>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <clock offset='localtime'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/bin/kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/images/VM-34.raw'/>
      <target dev='vda' bus='virtio'/>
      <alias name='virtio-disk0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </disk>
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='/images/virtio-win-1.1.16.iso'/>
      <target dev='hdc' bus='ide'/>
      <readonly/>
      <alias name='ide0-1-0'/>
      <address type='drive' controller='0' bus='1' unit='0'/>
    </disk>
    <controller type='ide' index='0'>
      <alias name='ide0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    </controller>
    <interface type='bridge'>
      <mac address='52:54:00:8a:19:bb'/>
      <source bridge='br0'/>
      <target dev='vnet0'/>
      <model type='e1000'/>
      <alias name='net0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </interface>
    <serial type='pty'>
      <source path='/dev/pts/1'/>
      <target port='0'/>
      <alias name='serial0'/>
    </serial>
    <console type='pty' tty='/dev/pts/1'>
      <source path='/dev/pts/1'/>
      <target type='serial' port='0'/>
      <alias name='serial0'/>
    </console>
    <input type='tablet' bus='usb'>
      <alias name='input0'/>
    </input>
    <input type='mouse' bus='ps2'/>
    <graphics type='vnc' port='5900' autoport='no' listen='0.0.0.0' keymap='de'/>
    <video>
      <model type='vga' vram='9216' heads='1'/>
      <alias name='video0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <alias name='balloon0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </memballoon>
  </devices>
</domain>

LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin HOME=/ QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-0.12 -enable-kvm -m 4096 -smp 4,sockets=4,cores=1,threads=1 -name VM-34 -nodefconfig -nodefaults -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/VM-34.monitor,server,nowait -mon chardev=monitor,mode=readline -rtc base=localtime -boot dc -drive file=/images/VM-34.raw,if=none,id=drive-virtio-disk0,boot=on,format=raw -device virtio-blk-pci,bus=pci.0,addr=0x6,drive=drive-virtio-disk0,id=virtio-disk0 -drive file=/images/virtio-win-1.1.16.iso,if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw -device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev tap,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=00:00:00:00:00:00 -chardev pty,id=serial0 -device isa-serial,chardev=serial0 -usb -device usb-tablet,id=input0 -vnc 0.0.0.0:0 -k de -vga std -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3