On 03/31/2015 07:12 AM, Satya Prasad Nemana wrote: > Gurus, > > I need clarity on what each item means and how it maps to the info we find on > dmidecod or lscpu on the host when creating a guest from the virt-manager. > > My question: > > 1) Under CPUs , we have Logical Host CPUs: What number does it indicate? Is > the max value that can be configured here the Cores* hyperthreads on the host?
Logical CPUs = Host Sockets * Host Cores * Host Threads > 2) Under Topology : we have sockets, cores , threads : do these correspond to > the outputs from dmidecode? > Socket Designation: Proc 1 > Core Count: 10 > Core Enabled: 10 > Thread Count: 20 libvirt/virt-manager gets the info from /proc/cpuinfo, but it should be the same numbers. > 3) Under Pinning, we have VCPU, On CPU, Pinning > : what do these values indicate VCPU number corresponds to the emulated VM CPU. So if you tell virt-manager to give your VM 8 CPUs, under VCPU pinning you will see VCPU number 0-7. Pinning allows you to say 'VM CPU 2 only uses Host CPU 3-4' which may be useful for specific performance scenarios. FWIW in newer versions of virt-manager the VCPU pinning UI is removed, but you can still do the same using the 'virsh' cli tool > does each vcpu value correspond to each virtual cpu on the host (obtained by > threads per core * number of cores) > [root@sienna ~]# lscpu > Architecture: x86_64 > CPU op-mode(s): 32-bit, 64-bit > Byte Order: Little Endian > CPU(s): 20 > On-line CPU(s) list: 0-19 > Thread(s) per core: 2 > Core(s) per socket: 10 > Socket(s): 1 > > If there is any detailed documentation anywhere, could someone please point me > to that ? > Dan has an overview of some of the various options here: https://www.berrange.com/posts/2010/02/12/controlling-guest-cpu-numa-affinity-in-libvirt-with-qemu-kvm-xen/ - Cole _______________________________________________ virt-tools-list mailing list virt-tools-list@redhat.com https://www.redhat.com/mailman/listinfo/virt-tools-list