Dear yuanle, Thank you for the information. You might be right. But I am still confused about what’s the difference between a vCPU and a physical core. Regards, Cheng From: sylecn [mailto:sylecn@gmail.com] Sent: 2014年3月17日 15:06 To: WANG Cheng D Cc: libvirt-users(a)redhat.com Subject: Re: [libvirt-users] a question on vCPU setting for lxc Hi, I'm not libvirt expect. My guess is that some vcpu settings only apply to KVM/qemu backend. LXC is quite different from them. If setting vcpu# is not effective for LXC container, you may need to use cgroups. -- Thanks, Yuanle On Mon, Mar 17, 2014 at 2:32 PM, WANG Cheng D <Cheng.d.Wang@alcatel-sbell.com.cn<mailto:Cheng.d.Wang@alcatel-sbell.com.cn>> wrote: Dear all, I am not clear about the ‘vcpu’ element for CPU allocation. I allocated 1 vCPU to my container, after I started the container, I ran 4 computation-intensive tasks on the container. And I found all the 4 physical core are 100% used (my host has 4 physical cores and no other application ran on the host except the container). That is, all available cores were used by the container. I want to know how to give a hard limitation for CPU usage of a container. So I don’t understand what ‘vcpu’ setting can be used for. I know that another CPU allocation element ‘shares’ can also be used, but this elements only give a relative quota. If new containers are started, the CPU quota for the already started containers will change. Regards, Cheng _______________________________________________ libvirt-users mailing list libvirt-users@redhat.com<mailto:libvirt-users@redhat.com> https://www.redhat.com/mailman/listinfo/libvirt-users