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Host CPU usage is registered in XP Guest...is this normal?

Posted: 6. Sep 2009, 21:07
by simulacrum111
Hello,

I am using virtualbox 3.0.6 beta but I have had the same problems with 3.0.4. I have an XP Home guest running on an Kubuntu 9.04 host.

My XP guest crashes any time I try to do anything CPU intensive. For example parallel builds of large code libraries.

I have not be able to figure out why but I have seen something I think is strange going on.

When I do something CPU intensive on my linux host I can see that the reported CPU usage in my guest increases even if my guest is basically idle. For example the task manager in XP reports high CPU usage in my guest when in fact I am only doing work in my Kubuntu host.

I don't understand why the reported CPU usage of my guest would be affected by the CPU usage of my host. I do understand that my guest would have less CPU available to it.

Is this normal? If not how do I submit a good bug report and where? (how do I get info from virtualbox to upload with the bug report) I think this is the likely source of my guest XP crashes. No?

Re: Host CPU usage is registered in XP Guest...is this normal?

Posted: 6. Sep 2009, 21:42
by Sasquatch
When you use your Host CPU and the Guest shows it too, can you provide a snapshot of top showing which process on the Host is taking the CPU and the Guest Taskmanager to show which process there is doing the use? It would help if it's in one shot, so open taskmanager, sort on CPU use and have top running on top of it. Then bump your CPU using the Host by compiling something for example and make a full screen shot. You can attach it here.

Re: Host CPU usage is registered in XP Guest...is this normal?

Posted: 6. Sep 2009, 21:45
by simulacrum111
Yes. I can do that. Give me a moment and I will update this post.

EDIT: THE REQUESTED IMAGES ARE BELOW.

I had to use image shack because my pngs were large according to this forum's rules.

I can post more images if these aren't clear enough or don't provide the information desired.

Image

Image

Image

Image

Re: Host CPU usage is registered in XP Guest...is this normal?

Posted: 6. Sep 2009, 22:15
by simulacrum111
In the above images you can see that I am compiling one of my projects using the Netbeans IDE. You can clearly see the Qt/KDE theme on the IDE in the lower left of the screen. Just above the editor you can see the familiar system monitor found in many linux distros. To the right you can see XP task manager. Note that it is reporting high CPU usage. Note also that there are no application open on the sidebar...because I am doing exactly NOTHING in my XP guest while compiling the previously mentioned project in my Kubuntu host.

Are the images clear enough? I hope I explained what is happening in them well enough.

edit::

I updated the pics post with pics with captures of per-process CPU usage in the XP guest.

Re: Host CPU usage is registered in XP Guest...is this normal?

Posted: 6. Sep 2009, 22:38
by Sasquatch
It's too bad the resolution is too low to properly read the Windows processes. I can see that System is taking about 43% and lsass.exe about 25%. You didn't sort the task manager by CPU usage, like I asked either.
I do see that you use SMP and gave the VM all four cores of your Host. That might explain why you see the usage on the Guest, it might be reading the actual CPU load, instead of the load the Guest OS is generating.

Re: Host CPU usage is registered in XP Guest...is this normal?

Posted: 6. Sep 2009, 23:05
by simulacrum111
Sasquatch wrote:It's too bad the resolution is too low to properly read the Windows processes. I can see that System is taking about 43% and lsass.exe about 25%. You didn't sort the task manager by CPU usage, like I asked either.
I do see that you use SMP and gave the VM all four cores of your Host. That might explain why you see the usage on the Guest, it might be reading the actual CPU load, instead of the load the Guest OS is generating.
I'll provide links to full resolution pictures in the post shortly.

I did sort the task manager by CPU usage. Highest use is at the top and lowest is at the bottom. I simply clicked on the task manager by accident while trying to set up my captures.

I do use SMP. However, I really don't see where there would be any logical distinction between giving my guest 2 or 4 CPUs. My guest shouldn't know what my host is doing. There should be separation there. My guest is just a process on the the host that uses X number of threads. For completeness sake I will restart my VM momentarily and reserve one SMP core for sole host use and see if it changes anything.

Here are the links to the full resolution images seen in the previous post:

http://img512.imageshack.us/img512/5218/snapshot1i.png
http://img134.imageshack.us/img134/6177/snapshot2f.png
http://img134.imageshack.us/img134/6428/snapshot4z.png
http://img29.imageshack.us/img29/1795/snapshot8c.png

Re: Host CPU usage is registered in XP Guest...is this normal?

Posted: 6. Sep 2009, 23:14
by simulacrum111
Originally I gave my XP guest access to 4 virtual CPUs. I reduced my XP guest's resources to 2 virtual CPUs.

There was no change in behavior. If I start a CPU intensive application in my Kubunu host high CPU usage is reported by my XP guest.

Re: Host CPU usage is registered in XP Guest...is this normal?

Posted: 6. Sep 2009, 23:34
by Sasquatch
I'm out of ideas. I don't have the hardware to confirm or otherwise test this.

Re: Host CPU usage is registered in XP Guest...is this normal?

Posted: 6. Sep 2009, 23:36
by simulacrum111
Sasquatch wrote:I'm out of ideas. I don't have the hardware to confirm or otherwise test this.
I understand completely. Thank you for your time.

Hopefully, someone else will think of something. I will probably need to figure out how to submit a decent bug report.

Re: Host CPU usage is registered in XP Guest...is this normal?

Posted: 8. Sep 2009, 19:58
by simulacrum111
I have submitted a bug report here:
http://www.virtualbox.org/ticket/4922

If anyone has anything to offer please post here or are suffering the same problems please corroborate the bug by posting your information on the linked bug ticket.