libvirt users - Mar 2014 - Re: Problem in getting memory statistics

Hello,
I need to get how much memory is used by a guest system, in order to
implement some monitoring function which tells me if the system is
overstressed.

I am currently using java apis and the binding which was suggested to me was
Domain.memoryStats();

This is a binding to  int virDomainMemoryStats
(virDomainPtr<http://libvirt.org/html/libvirt-libvirt.html#virDomainPtr>dom,
virDomainMemoryStatPtr<http://libvirt.org/html/libvirt-libvirt.html#virDomainMemoryStatPtr>stats,
 unsigned int nr_stats, unsigned int flags).

Problem is that it returns me just tags 0,6 and 7.
Looking at the documentation I see they are not what I am looking for...I
would rather need 4 (VIR_DOMAIN_MEMORY_STAT_UNUSED) and 5
(VIR_DOMAIN_MEMORY_STAT_AVAILABLE).

Is there a way to set them?

At Wed, 12 Mar 2014 13:36:50 +0100,
Pasquale Dir wrote:
> 
> Hello,
> I need to get how much memory is used by a guest system, in order to
> implement some monitoring function which tells me if the system is
> overstressed.
> 
> I am currently using java apis and the binding which was suggested to me
was
> Domain.memoryStats();
> 
> This is a binding to  int virDomainMemoryStats
>
(virDomainPtr<http://libvirt.org/html/libvirt-libvirt.html#virDomainPtr>dom,
>
virDomainMemoryStatPtr<http://libvirt.org/html/libvirt-libvirt.html#virDomainMemoryStatPtr>stats,
>  unsigned int nr_stats, unsigned int flags).
> 
> Problem is that it returns me just tags 0,6 and 7.
> Looking at the documentation I see they are not what I am looking for...I
> would rather need 4 (VIR_DOMAIN_MEMORY_STAT_UNUSED) and 5
> (VIR_DOMAIN_MEMORY_STAT_AVAILABLE).
The information available depends on the kind of hypervisor you're
using and which guest OS you have.

I guess you're using qemu.  Which version are you using?

What guest OS do you use? Which version?

What's the version number of the balloon driver inside your guest?

[ideally, you should always provide at least the hypervisor and guest
 OS information without us having to ask you]

I have another problem.
As in java bindings there is no way to obtain cpu stats I decided to use a
python script.
It gives me, for the guest domain, cpu time, system time and user time.
Now, what does it mean cpu time? I though that it could be the overall cpu
time given to this vm...but the sum doesn't add up: user_time+system_time
!= cpu_time.
As I would need to get a %cpu usage, like virt-manager does (so it IS
possible, and it IS in python), what operation do I need to do to make this
happen?


2014-03-12 13:36 GMT+01:00 Pasquale Dir <phate867@gmail.com>:
> Hello,
> I need to get how much memory is used by a guest system, in order to
> implement some monitoring function which tells me if the system is
> overstressed.
>
> I am currently using java apis and the binding which was suggested to me
> was
> Domain.memoryStats();
>
> This is a binding to  int virDomainMemoryStats
(virDomainPtr<http://libvirt.org/html/libvirt-libvirt.html#virDomainPtr>dom,
>
virDomainMemoryStatPtr<http://libvirt.org/html/libvirt-libvirt.html#virDomainMemoryStatPtr>stats,
>  unsigned int nr_stats, unsigned int flags).
>
> Problem is that it returns me just tags 0,6 and 7.
> Looking at the documentation I see they are not what I am looking for...I
> would rather need 4 (VIR_DOMAIN_MEMORY_STAT_UNUSED) and 5
> (VIR_DOMAIN_MEMORY_STAT_AVAILABLE).
>
> Is there a way to set them?
>

[please don't top post on technical lists. it is easier to follow
 conversation and less likely you forget answering a question if
 you reply to the questions in line]

[please keep the conversation on the list - I've re-added libvirt-users]

At Sat, 15 Mar 2014 10:15:15 +0100,
Pasquale Dir wrote:
> 
> I am on a kubuntu 13.10 x64, qemu version 1.5.0, guest uses kvm as emulator
> (1.5.0 as well), libvirt version is 1.1.1.
> I don't know what is a balloon driver...so I can't tell the version
of it.
If you're using Linux inside your guest, just run "modinfo
virtio_balloon" and post the output.
> 2014-03-14 12:00 GMT+01:00 Claudio Bley <cbley@av-test.de>:
> 
> > At Wed, 12 Mar 2014 13:36:50 +0100,
> > Pasquale Dir wrote:
> > >
> > > Problem is that it returns me just tags 0,6 and 7.
> > > Looking at the documentation I see they are not what I am looking
for...I
> > > would rather need 4 (VIR_DOMAIN_MEMORY_STAT_UNUSED) and 5
> > > (VIR_DOMAIN_MEMORY_STAT_AVAILABLE).
> >
> > The information available depends on the kind of hypervisor you're
> > using and which guest OS you have.
> >
> > I guess you're using qemu.  Which version are you using?
>
> > What guest OS do you use? Which version?
Er, you missed this question...

At Sat, 15 Mar 2014 23:33:59 +0100,
Pasquale Dir wrote:
> 
> I have another problem.
> As in java bindings there is no way to obtain cpu stats I decided to use a
> python script.
> It gives me, for the guest domain, cpu time, system time and user time.
> Now, what does it mean cpu time? I though that it could be the overall cpu
> time given to this vm...but the sum doesn't add up:
user_time+system_time
> != cpu_time.
> As I would need to get a %cpu usage, like virt-manager does (so it IS
> possible, and it IS in python), what operation do I need to do to make this
> happen?
Have a look at the implementation of the _sample_cpu_stats method of
the vmmDomain class here:

https://git.fedorahosted.org/cgit/virt-manager.git/tree/virtManager/domain.py