virtualbox.org

Hi,
Green and pink colors would appear in the processor setting bar in setting for Oracle VM manager in normal case.

But in my case, it shows all in pink, I do doubt it indicates something wrong.

The computer( I use, actually a server): 56 cores (112 processors).

The processor setting in VirtualBox Manager on the computer is pink. see the image below.

Also, it shows 32 CPUs, which I can not figure out how the VirtualBox Manager gets this number.

So, something went wrong or different. Please help find out.

Thanks!

Pick a VM and provide a VM log file. With the VM fully shut down, right click it in the GUI. Select "Show Log" and save "VBox.log" (no other file) to a zip file. Attach the zip here.

First, the "virtualization technology" bit in the computer's BIOS is probably not on. See I have a 64bit host, but can't install 64bit guests, post 1.

You should see a green portion after turning this on. If not, check if Hyper-V is on, and turn it off. See posts 2 & 3 in the 64-bits link.

If you still see less than the maximum processors available on the slider, this would probably be a hard-coded limitation in the GUI. You would need to use 'vboxmanage' on the command line to add more processors to a VM.

Adding more processors only helps when the OS in the VM has more data to process than it can with the processors it has now. Extra processors make a VM run slower, due to extra scheduling overhead in the host OS. If the OS in the VM does not have enough data to use up all its processors, the data will execute more slowly. A typical Windows or Linux OS likes two processors for its typical usage. Only add processors if the VM is fully stabilized after install, and you add your own programs, and the VM is still running 100% and your added programs have lots of multi-processing parallel threads.

qiping wrote: 56 cores (112 processors).

This is probably 56 hyperthreaded cores. For Virtualbox purposes, only the cores count. Hyperthreads don't help a Virtualbox guest. So you have a maximum of 56 cores (55, actually, the host needs one) to assign to guests. And as mentioned above, only assign all 55 to one guest if there is 55 cores' worth of parallel threads to process, as well as memory and disk bandwidth, or the VM will execute as slow as an 8086....

Here is the VBox.log file zipped.

Hi scottgus1, thanks for your reply.

In BIOS, I have Virtualization technology enabled.
Hyper-V has also disabled.
There is still no green portion.

Yep, VT-x is enabled:

00:00:02.897650 HM: HMR3Init: VT-x w/ nested paging and unrestricted guest execution hw support

Nice computer!

00:00:02.754981 Host RAM: 522910MB (510.6GB) total, 509033MB (497.1GB) available
00:00:03.813216 CPUM: Physical host cores: 56

I think you're going to have to ship this computer to me so I can troubleshoot...

You were able to put 4 cores in your guest:

00:00:02.896901 NumCPUs <integer> = 0x0000000000000004 (4)

I would ignore the lack of green in the slider. It's probably an error in the GUI code. Most users of Virtualbox probably don't have 56-core computers.

that the processor setting bar does not have green portion does not have any connection to any 'bad' performance inside the VM?
also what if I want to create a VM with the number of cpus larger than 32?

qiping wrote:that the processor setting bar does not have green portion does not have any connection to any 'bad' performance inside the VM?

I believe not. It's just graphics to encourage people not to put lots of cores in a guest.

qiping wrote:what if I want to create a VM with the number of cpus larger than 32?

Get the PDF of the Virtualbox manual: https://download.virtualbox.org/virtual ... Manual.pdf You can search the text.

This command sets the CPU count:

the manual wrote:vboxmanage modifyvm "vm name" --cpus <cpucount>
Sets the number of virtual CPUs for the virtual machine, see chapter 3.5.2, Processor Tab

Thanks very much!

qiping wrote:The computer( I use, actually a server): 56 cores (112 processors).

This is recognized by the VirtualBox CPU Manager:

VBox.log file wrote:

00:00:03.813214 CPUM: Logical host processors: 112 present, 112 max, 112 online, online mask: ffffffffffffffff
00:00:03.813216 CPUM: Physical host cores: 56

---

qiping wrote:Also, it shows 32 CPUs, which I can not figure out how the VirtualBox Manager gets this number.

You can read viewtopic.php?f=8&t=98388&start=15#p477214 for a partial explanation of that. At least in VirtualBox 6.1.8, I'd expect the maximum value of the slider to be 64 in your case. Do you use an older version of VirtualBox?

Regarding the invisible green slider part, my educated guess is that the method used by the VirtualBox Manager is not suited for large processor core counts and returns 0. I don't know if that has any further significance.