Vagrant VBox configuration multiple cpus

VagrantfileMultipleCpus.rb

config.vm.provider :virtualbox do |vb|
  #   # Don't boot with headless mode
  #   vb.gui = true
  #
  #   # Use VBoxManage to customize the VM. For example to change memory:
    vb.customize ["modifyvm", :id, "--memory", "1024"] #memory to 1GB
    vb.customize ["modifyvm", :id, "--cpuexecutioncap", "50"] #limit the use of cpu to 50%
    vb.customize ["modifyvm", :id, "--ioapic", "on"] #needed to use more cpus
    vb.customize ["modifyvm", :id, "--cpus", "2"]  #enable 2 cpus for the vm
  end