Thank you. Do you mean that if the host isn't busy and VCPU=4, CPU=1 and CPU=2 have the equal effect. So CPU has effects only when the host os is overcommited.
At 2013-01-24 14:28:32,"Rolandas Naujikas" <rolandas.nauji...@mif.vu.lt> wrote: >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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