I've installed Ubuntu in a virtual environment using Oracle VM VirtualBox Manager and it works great.
However I'd like to enable multiple cores – as seen in the image below my Windows machine has 2 cores:
Now when I run the lscpu
in Ubuntu I get the following info revealing that only 1 core is being utilized:
I've tried changing the settings of the virtual box to enable multiple processors but it won't allow me to do so as shown in the image below:
How do I enable multiple cores (processors) in my virtual enviroment?
Best Answer
To enable more than 1 CPU in your VM the following settings are needed in addition:
64-bit virtual guest hardware in General settings tab (for 64-bit guests)
enable I/O APIC in the Motherboard settings tab
enable hardware virtualization (VT-x/AMD-V) in the Acceleration tab
Note that if your run your VM on all cores available you may experience a better host performance when assigning an execution cap to the CPU.
If you had not enabled hot-plug CPU feature of virtualbox changing of the number of cores can only be done on a machine that was shut down.
A performance boost in the guest is only to be expected for software that makes use of several cores. Only then giving all cores with an execution cap makes sense.