[Pkg-libvirt-maintainers] Bug#672720: Bug#672720: libvirt-bin: KVM domains suspended with virsh suspend still use CPU time

[Guido Günther]

On Sun, May 13, 2012 at 11:37:35AM +0300, Kari Pahula wrote:
> Package: libvirt-bin
> Version: 0.9.11.3-1
> Severity: wishlist
> 
> I ran some tests with powertop and a wattmeter, and I'm not sure if
> virsh suspend really does what it says.
> 
> With my system idle, no kvm domains running, powertop shows over 99%
> C2 state and wattage goes down to almost 60W.
> 
> When I start a kvm domain and the virtual machine is idling after
> booting, C2 state drops below 90%, wattage is at about 75W and top
> shows kvm using about 10% CPU time.
> 
> When I run virsh suspend, I see no change in system load.  Man page
> says:
> 
>   When in a paused state the domain will still consume allocated
>   resources like memory, but will not be eligible for scheduling by
>   the hypervisor.
> 
> Am I wrong in expecting to see my system load drop more towards the
> idle system situation with suspend?  What else is it doing besides
> keeping the domain in memory?

I'd check the monitor commands issued by libvirt and reproduce this with
stand alone kvm. Libvirt shouldn't be doing anything special here and
you should be able to check kvm's state. See also:

	http://www.linux-kvm.org/page/Tracing

Cheers,
 -- Guido

> 
> kvm doesn't like it if I kill -19 it...
> 
> -- System Information:
> Debian Release: wheezy/sid
>   APT prefers unstable
>   APT policy: (500, 'unstable')
> Architecture: amd64 (x86_64)
> 
> Kernel: Linux 3.2.0-2-amd64 (SMP w/6 CPU cores)
> Locale: LANG=C, LC_CTYPE=fi_FI.UTF-8 (charmap=UTF-8)
> Shell: /bin/sh linked to /bin/dash
> 
> Versions of packages libvirt-bin depends on:
> ii  adduser             3.113+nmu1
> ii  gettext-base        0.18.1.1-7
> ii  libavahi-client3    0.6.31-1
> ii  libavahi-common3    0.6.31-1
> ii  libblkid1           2.20.1-4
> ii  libc6               2.13-32
> ii  libcap-ng0          0.6.6-1
> ii  libdevmapper1.02.1  2:1.02.74-3
> ii  libgcrypt11         1.5.0-3
> ii  libgnutls26         2.12.19-1
> ii  libnetcf1           0.1.9-2
> ii  libnl1              1.1-7
> ii  libnuma1            2.0.8~rc3-1
> ii  libparted0debian1   2.3-9.1
> ii  libpcap0.8          1.2.1-2
> ii  libpciaccess0       0.13.1-2
> ii  libreadline6        6.2-8
> ii  libsasl2-2          2.1.25.dfsg1-4
> ii  libudev0            175-3.1
> ii  libvirt0            0.9.11.3-1
> ii  libxenstore3.0      4.1.2-6
> ii  libxml2             2.7.8.dfsg-9
> ii  libyajl2            2.0.4-2
> ii  logrotate           3.8.1-1
> 
> Versions of packages libvirt-bin recommends:
> ii  bridge-utils    1.5-2
> ii  dmidecode       2.11-6
> ii  dnsmasq-base    2.61-1
> ii  ebtables        2.0.9.2-2.1
> ii  gawk            1:4.0.1+dfsg-1
> ii  iproute         20120319-1
> ii  iptables        1.4.13-1.1
> ii  libxml2-utils   2.7.8.dfsg-9
> ii  netcat-openbsd  1.105-6
> ii  parted          2.3-9.1
> ii  qemu            1.0.1+dfsg-1
> ii  qemu-kvm        1.0+dfsg-11
> 
> Versions of packages libvirt-bin suggests:
> pn  policykit-1  0.105-1
> pn  radvd        <none>
> 
> -- no debconf information
> 
> 
> 
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