On 2013-01-24 05:52, cmcc.dylan wrote:
what's more, libvirt cann't see the CPU parameter! sou i think CPU is only used for overcommiting in opennebula level.
In Xen/KVM it is passed to Xen credit scheduler or KVM cgroup configuration for minimal CPU share. So if you put CPU=0.25,VCPU=1, then 1 KVM thread will use 1 host CPU, until host becomes too busy, then it tries to schedule at least 0.25 of 1 host CPU (core) time.
Regards, Rolandas Naujikas
At 2013-01-24 11:42:31,"cmcc.dylan" <dx10ye...@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" <t...@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-boun...@lists.opennebula.org [mailto:users-boun...@lists.opennebula.org] On Behalf Of cmcc.dylan Sent: Wednesday, January 23, 2013 9:26 PM To:users@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". -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.opennebula.org/pipermail/users-opennebula.org/attachments/20130124/ac145e09/attachment.htm>
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