[Xen-users] CPU monitoring & CPU cycles

[Marco Creola <marco_creola@xxxxxxxx>]

Hi.

I am a student at University of Zurich and I'm doing a homework about
Cloud Computing regarding accounting and billing.

Because the "big" players use Xen Hypervisor I installed a Xen (3.3.0)
on an Ubuntu 8.04 to test some things and get more familiar with Xen
regarding accounting.

I have two questions:

1. CPU monitoring
+++++++++++++++++
I have discovered something strange regarding CPU usage monitoring.

I found a CPU monitoring tool called "xenmon.py".

I have to explain my problem with the help of a screenshot.

On top left side on "screenshot.png" you can see that Dom0 is pinned to
CPU 0 and my two VMs are pinned to CPU 1. (Both VMs use also Ubuntu
8.04).

Also you can see that vm2 and vm3 have each a cap of 40%.

On the left side on the picture you can see that I made some stress test
on both VMs.

On the bottom right side of the screenshot I monitor CPUs with XenMon.
As I've excepted XenMon shows that vm2 and vm3 only use 40% each of
their pinned core and therefore this core is used 80%.

But if you look on the top right side, where Ubuntu's built-in system
monitor and a terminal with "htop" inside lie, the CPU usage is
completly different - at least for the CPU which is used by the VMs.

Ubuntu says that CPU 2 uses 22.5% but XenMon says that this CPU has a
load of 80%.

Why is this difference? Is this a lack of Ubuntu or of XenMon? Which
monitor can I trust?


2. CPU cycles
+++++++++++++
Is there a way to monitor or to log CPU cycles? For example I would like
to know how many CPU cycles "vm2" uses. Maybe there is no tool, but
could this be possible through the Xen API? I have searched the Xen
documentation but I have not found anything.


English is not my native language, so if I sound rude or impolite, I
apology.

I appreciate every help. Thanks a lot.

Kind regards,
Marco

screenshot.png
Description: PNG image

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