Slow performance on Linux Host 64 bit

[Antimo]

I'm experiencing very low performance on Linux Ubuntu Host 64 bit with a Windows 7 64 bit Guest (i.e the guest go slowwww)

i have tried different hardware (Intel or AMD) for hosting system but with the same result.

I have high cpu utilization on the host and low performance on guest all things are slow in guest system. Even with a fresh windows 7 installation

It didn't happen until the last 4-6 days, don't know if it's update related.
Any hint?

[mpack]

How many cores does the host have, and how many cores have you assigned to the guest?

You have not really provided enough pertinent info. It may help if you posted the VM log file, as a zipped attachment please.

[Antimo]

Ok, thk you for the answer.
I have an I7 cpu Q 720 (reported as a 4 core) and i assign to the Guest tre processor (core)

Attach the log + the CPU info of the host

Host info uname -a
Linux UbuntuLavoro64 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:33:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

The problem appear after some minute (20 minute or so) this time.
When the problem start, the cpu utilization in the host rump up and in the top command of the Host appear a kworker thread that eat all of the cpu (100% at least one core i think).
Cpu guest appear to be normal (until the guest work i can see it).
The is no way to recover from the situation , i have to restart the host sistem which remain working but with the cpu at 100% assigned to the worker thread. The guest stop working and there is no way to shutdown the guest. Even the host didn't do a complete Restart (i really unplug the power to recover)

Feel free to ask me every information you need

[mpack]

The problem appear after some minute (20 minute or so) this time.

It sounds like there may be a background process kicking in, e.g. the disk defragmenter, or an antivirus scan. You might want to check the VMs task manager when this happens, look for a CPU or IO hog. I see nothing of interest in the log.

[Antimo]

AFAIK the kworker thread have to be released when the machine has stopped, or may be return to a normal cpu utilization

Anyway the problem happen even on a fresh Windows 7 installation whit no antivirus. I could recreate the problem on differe 64 bit Host (AMD or Intel).

Precisely on the AMD everything slow down but keep working, on Intel host i need to unplug the host to reestabilish control.

Could be useful open a bug request?

[mpack]

A bug report would probably only get any attention if you could provide enough information to ensure that the problem can be reproduced.

[Antimo]

Ok, i could collect any information the support may need, i could reporduce the problem simply restarting the VM .

But i need to be instructed on what collect and how to collect, i'm non an matter expert, even if i worked in Sun / Oracle until one year ago

So it's better to collect info here or on https://www.virtualbox.org/wiki/Bugtracker? For me it's the same, i'll do the best

Thank you

Antimo