[New KVM concept]-Virtual Machine CPU Hot plugging

[KVM New Concept]-Virtual Machine CPU Hot Plug-in background CPU and memory hot plug-in has been supported by mainstream operating systems for a long time. Microsoft has started to support it since Windows Server 2008, linux is supported from the kernel 3.2.0. Status Qemu has also planned the CPU Hot plugging feature for a long time, but it has not been integrated into the master-stem version, because there are many bugs and restrictions in implementation. The latest hot plugging branch of cpu is: https://github.com/imammedo/qemu/tree/cpu_add.v2 Currently, only vcpu Hot Plug-in is implemented, and hot unplug is not supported. I only verified the CPU hot-plug in the ora 18 client. step I specifically optimized qemu-kvm for Fedora 18, mainly optimizing qemu on IA 64, KVM and Linux to improve the stability and performance of qemu-kvm. The git repository is https://github.com/luohao-brian/qemu-kvm . You are welcome to try it out. Checkout branch qemu. dev. cpu_add and build qemu-kvm rpm packages; $ git clone https://github.com/luohao-brian/qemu-kvm $ Git checkout-B cpu_add remotes/origin/qemu. dev. cpu_add $ cp qemu-kvm.spec ~ /Rpmbuild/SPECS/$ rpmbuild-ba ~ /Rpmbuild/SPECS/qemu-kvm.spec $ rpm-Uvh qemu-common-1.4.0-10000.x86_64.rpm qemu-kvm-1.4.0-10000.x86_64.rpm qemu-img-1.4.0-10000.x86_64.rpmLaunch a guest which supports cpu hotplug like F18 or Win 2008 with a qemu qmp server: $ qemu-kvm-cpu host-enable-kvm-m 1024-smp 2, maxcpus = 4-drive file =/root/f18-live.iso-qmp tcp: localhost: 4444, server Connect to the qmp server using telnet $ telnet localhost 4444 Issue the json command as follows to check qmp capabilities, otherwise the following cpu-add command does not work. INPUT: {"execute": "qmp_capabilities"} OUTPUT: {"return" :{}} Issue the json commands to add vcpus to the guest: INPUT: {"execute ": "cpu-add", "arguments": {"id": 2 }}output: {"return" :{}} INPUT: {"execute ": "cpu-add", "arguments": {"id": 3 }}output: {"return" :{}} Go check the guest, and if it is a linux, you will see 2 cpus have been made available under/sys/devices/system/cpu /. to activate either of them, issue a command like: $ echo 1>/sys/devices/system/cpu/cpu2/online