UK BOINC Team Forum

When I created my virtual machine I tried to give it 4 processors as I have a quad processor host. However it doesn't allow more than 2 as it says it is more than I have available on the host. I presume this s because my host is actually 2 CPUs each with two threads. However on the virtual machine it only runs two copies of Wanless at a time. Is there anything I can do about this or is it just the limit? Should I create a second Vbox? Now I know what to do I can have another running within the hour.

Thanks,

Chris.

Hi Chris

Can you process 4 concurrent BOINC tasks when running Windows?

(If you can, then the idea I had was that maybe your BIOS is not "allowing" all 4 vCores to be accessed by VBox? - but if you can do this, then my idea falls flat on it's face )

The other thing is that maybe you need at least 1x CPU for WIndows to run - otherwise maybe the VBox cannot work if it is competing with Windows for "CPU time". Are you running a BOINC task that is using the GPU?

regards
Tim

Hi Chris,

Terminology as far as Virtualbox is concerned:
CPU - Physical device, you have one CPU
Cores - processing devices, you have two cores
Threads - number of consecutive execution units, you have four threads.

When assigning resources to Virtualbox it works on cores not threads so it sees your CPU as two cores.

If you have hyperthreading turned on in the BIOS then you should be able to specify four cores even though Virtualbox will give you a warning. How is it not allowing it?

As an aside, you shouldn't assign all the resources to the VM as you'll need some for the host to run, service and control the VM. Three is probably the most you should use.

Woodles wrote: ↑Wed Jun 03, 2020 5:31 pm
If you have hyperthreading turned on in the BIOS then you should be able to specify four cores even though Virtualbox will give you a warning. How is it not allowing it?

When I go into 'settings' then 'System' and the 'processors' if I try to slide the pointer beyond two a little icon pops up at the bottom saying 'Invalid parameter' or somesuch.

I'll just stick with the one dual core VM for now then. If Wanless isn't selected then it's a bit of a moot point and I'll have a bit more time to ponder the problem then.

Thanks,

Chris.

That's because it thinks you only have two cores, you should be able to select three if you wanted.

Mark,

Once again you're perfectly right. Just ignore the warning, carry on regardless and it works OK with three processors.

Jobs a good 'un.

Chris.