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Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 20. Nov 2009, 13:07
by abcuser
Hi,
I have a desktop PC that supports VT-x and has single dual core processor. I have virtual machine that had 1 CPU defined. Now I have changed in VirtualBox GUI to 2 CPUs. Starting guest OS and I still see only one CPU (single column in Windows Task Manager). Is this OK? What does it means "Processors" in VirtualBox? Is it physical processor or it should also run on dual-core single CPU?
Regards

My system:
- Ubuntu 8.04 LTS (host),
- VirtualBox 3.0.10,
- Windows XP SP3 (guest.

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 20. Nov 2009, 13:30
by Sasquatch
Please use the search as described in the Forum Posting Guide. You need to change the CPU driver before the guest can use the second core/CPU.

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 20. Nov 2009, 20:53
by abcuser
Sorry, I have already googled around and just can't fine any useful info about 2-cpus. "Change CPU driver"?

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 20. Nov 2009, 21:11
by Sasquatch

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 23. Nov 2009, 14:08
by abcuser
Hi,
I have set 2 CPUs in VirtualBox GUI and then started virtual machine and followed external links about settings 2 CPUs:
1. I removed CPU drivers from Device Manager in Windows XP SP3.
2. Reboot
3. Install CPU driver - there was no "ACPI Multiprocessor PC" available to select from. It was only "Intel Processors" and "Processors" - I selected Intel.
4. Reboot
5. In Device Manager there are two processors displayed, but in Task Manager these is only one CPU displayed.

BTW, today I have upgraded to VBox 3.0.12.

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 23. Nov 2009, 14:49
by Sasquatch
Check the View section of Task Manager. You can let it show one graph for both CPU's, or one per CPU.

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 24. Nov 2009, 09:52
by abcuser
Hi,
I have checked and there is only "one CPU".
Regards

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 24. Nov 2009, 10:52
by Sasquatch
Then it seems that the only thing you see, is the HyperThreading feature of the CPU, instead of the real two cores/CPUs you gave it. Or, that's also possible, you don't have the multiprocessor kernel running.

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 24. Nov 2009, 12:07
by MarkCranness
Sasquatch wrote:Or, that's also possible, you don't have the multiprocessor kernel running.
I think that's the case. To get 'ACPI Multiprocessor PC', you will likely have to install it from your original install CD, or maybe it can be obtained from Windows Update. Do the Device Manager>Update Driver thing, but with your XP install CD in your CD drive.

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 24. Nov 2009, 12:12
by Sasquatch
You should not need the Windows CD, but it's a good idea to keep it nearby.

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 24. Nov 2009, 13:04
by MarkCranness
Oh, IMPORTANT: Don't Update Driver your Processors, you must Update Driver your Computer (second item from the top).

In general, whether you need your XP install CD depends upon what has already been copied to your system32 folder.
If the 'ACPI Multiprocessor PC' HAL (=Halmacpi.dll) is already there, you won't need the CD, otherwise you will.

Or it may be harder than that...
http://support.microsoft.com/kb/309283
Windows XP Device Manager and Windows Server 2003 Device Manager list limited choices for changing your HAL type when you click Update Driver. ...
... I'm not sure that you will be able to select the 'ACPI Multiprocessor PC' HAL.
http://www.myitforum.com/articles/15/view.asp?id=8997

These links claims to have solutions:
http://www.hardware.info/en-US/news/ym2 ... t_anymore/
http://java.akraievoy.org/2009/01/chang ... p-hal.html
 

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 24. Nov 2009, 14:55
by abcuser
MarkCranness wrote:Oh, IMPORTANT: Don't Update Driver your Processors, you must Update Driver your Computer (second item from the top).
Hi,
you are right, I just updated the wrong driver. I should update "Computer" driver. I tried to update driver, but "ACPI Multiprocesor PC" is not listed in the list of available CPUs.
Regards

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 24. Nov 2009, 14:58
by abcuser
MarkCranness wrote:These links claims to have solutions:
http://www.hardware.info/en-US/news/ym2 ... t_anymore/
Hi,
thanks a lot. I have downloaded simple program to change HAL, start the program, select "ACPI Multiprocesor PC" and restarted Windows. After reboot I can see two CPUs in Windows. It looks like Windows didn't recognized the change of hardware...
Thanks a lot for help.
Regards

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 24. Nov 2009, 22:32
by FrodoHobbits
The zip file seems to be corrupt, could someone please post a location where I could download a clean zip file.
My searchs have come up with nothing.
Thanks in advance

Re: Is dual core CPU the same as 2 CPUs in VirtualBox?

Posted: 24. Nov 2009, 22:37
by Sasquatch
FrodoHobbits wrote:The zip file seems to be corrupt, could someone please post a location where I could download a clean zip file.
My searchs have come up with nothing.
Thanks in advance
Are you sure you're posting in the right place?