[libvirt-users] memoryStats question

[Claudio Bley]

At Fri, 04 Jul 2014 16:18:45 +0200,
Ján Tomko wrote:
> 
> [1  <text/plain; ISO-8859-1 (quoted-printable)>]
> On 07/04/2014 03:18 PM, Claudio Bley wrote:
> > At Thu, 03 Jul 2014 17:46:14 +0300,
> > Gleb Voronich wrote:
> >>
> >>
> >>> virDomainMemoryStats() gets those stats, if qemu is new enough to
> >>> provide them, and if the guest cooperates to provide them.
> >> Well I use the latest QEMU 2.0.0
> >> I have the latest CentOS 6.5 installed on the guest and unfortunately
> >> I can't get more stats that I have.
> >>
> >>> Which OS are you using in your guests?
> >>>
> >>> Of course, you need to have the virtio balloon driver up and runnig in
> >>> your guests.
> >> CentOS 6.5 x86_64
> >> It has the balloon driver and it is up and running:
> >>
> >> # modinfo virtio_balloon
> >> filename:
> >> /lib/modules/2.6.32-431.17.1.el6.x86_64/kernel/drivers/virtio/virtio_balloon.ko
> >> license:        GPL
> >> description:    Virtio balloon driver
> >> srcversion:     BB9F75B2CAF3435CC507998
> >> alias:          virtio:d00000005v*
> >> depends:        virtio,virtio_ring
> >> vermagic:       2.6.32-431.17.1.el6.x86_64 SMP mod_unload modversions
> > 
> > In this case, it's your guest kernel that's too old to support these
> > stats.
> > 
> > Apparently, reporting statistics in the balloon driver was introduced
> > in the kernel on 24th Feb 2010 (commit
> > 9564e138b1f6eb137f7149772438d3f3fb3277dd) which clearly predates
> > version 2.6.32 (2nd December 2009).
> 
> Acording to the kernel RPM's changelog, this was backported into 2.6.32-38.el6
> and released in RHEL 6.0 (Nov 2010):
> https://bugzilla.redhat.com/show_bug.cgi?id=601690

In that case, I'd guess that Gleb just forgot to call
virDomainSetMemoryStatsPeriod, perhaps?

Gleb, you didn't mention what language (binding) you're using.

In virsh, use the "--period N" option for the dommemstat command at least
once in order to enable stats collection.

-- 
Claudio