[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-discuss] High CPU in idle Windows guest

From: Jakob Bohm
Subject: Re: [Qemu-discuss] High CPU in idle Windows guest
Date: Tue, 12 May 2015 13:55:11 +0200
User-agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0

(top posting to keep thread consistent)

Then you should remember to pass the qemu options to
start the VM as a XEN DomU, not as a software VM inside
your current (Dom0) VM.

I think (from reading qemu --help) that you may need
to do that via something called xend, there is probably
a manual somewhere.

On 10/05/2015 17:14, Terry Glanfield wrote:
Hi Dave,

You do know that I'm running a Xen hypervisor and not KVM?

I'm not wedded to Xen and would consider using KVM if it's more likely
to solve my problem, but it would be good to get the Xen solution
working properly.


Dave Gosselin <address@hidden> writes:
Hi Terry,

It appears that the kernel driver hasn't been started.  You can do
this manually, before starting qemu, by running this as the root user:
modprobe kvm

You can confirm that the modprobe command started via the lsmod
command:  lsmod | grep -i kvm
If you see any entries, it's loaded; if the command returns with
nothing, then it did not load.

Afterwards, you can run qemu but you may have to run it as root for it
to take advantage of the KVM module you just started.


On 5/9/15 8:44 PM, Terry Glanfield wrote:
Hi Dave,

With -enable-kvm I get.

Could not access KVM kernel module: No such file or directory
failed to initialize KVM: No such file or directory

Where to next?  I'm willing to help diagnose it in whatever way I can.


Dave Gosselin <address@hidden> writes:
Try supplying the -enable-kvm option to your qemu arguments. If it
doesn't work then the support may not be compiled in to qemu or the
driver may not be loaded into the kernel. Let me know.
Dave Gosselin

Sent from my iPhone

On May 9, 2015, at 18:52, Terry Glanfield <address@hidden> wrote:


I'm running a freshly installed Windows 7 domU on an up-to-date Debian
jessie machine running Xen 4.4.1-9. When the Windows machine is idle,
I'm seeing upwards of 10% CPU usage from the qemu-system-i386 instance.
Other Linux and FreeBSD machines register negligable CPU usage (<0.5%).
The server is an HP Proliant DL360 G7.

PV drivers don't seem to make any difference.

Data from perf attacthed to the process might give the best clues.

Any information as to why this processes is comsuming so much CPU would
be much appreciated.




Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
This public discussion message is non-binding and may contain errors.
WiseMo - Remote Service Management for PCs, Phones and Embedded 

reply via email to

[Prev in Thread] Current Thread [Next in Thread]