[one-users] the problem of the CPU in the virtual machine's template

[cmcc.dylan]

what's more, libvirt cann't see the CPU parameter! sou i think CPU is only used for overcommiting in opennebula level. 






At 2013-01-24 11:42:31,"cmcc.dylan" <dx10years at 126.com> wrote:


if VCPU=4, i think the host will fork 4 process on behalf of this vm, because i see it is so implemented in the qemu code.
I am very confused about this part of opennebula!


At 2013-01-24 11:31:34,"Steven C Timm" <timm at fnal.gov> wrote:


VCPU is the parameter that controls how many cores appear internally in the virtual machine.  I. e. if you have VCPU=4

Your VM will have 4 cores, but there will still only be one kvm process as seen in the hypervisor that corresponds to it.

In a typical KVM setup it is possible to allocate more VCPU per VM host than the VM host has real cores.

I am not exactly sure what CPU does, but it does affect the FCPU and ACPU as seen in the onehost list output.

 

Steve Timm

 

From:users-bounces at lists.opennebula.org [mailto:users-bounces at lists.opennebula.org] On Behalf Of cmcc.dylan
Sent: Wednesday, January 23, 2013 9:26 PM
To:users at lists.opennebula.org
Subject: [one-users] the problem of the CPU in the virtual machine's template

 

Hi, everyone!

 

    I have a doubt what's the accurately means of CPU in the vm's template. 

    For a example, if we define a vm which has CPU=1 and VCPU = 4. In this condition , what's result in the host os?

    Does the host os fork 4 process on behalf of this vm and does  the 4 process get 4 cores if the host's scheduler allows that.

 

    I want to know the differences between "CPU=4,VCPU=4" and "CPU=1,VCPU=4".

    

 



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