[libvirt-users] The accurate CPU usage of a domain?

Hi,all I want to get a relatively accurate cpu usage of a domain. I have a few questions about virDomainGetInfo: struct virDomainInfo{ unsigned char state : //the running state, one of virDomainState unsigned long maxMem :// the maximum memory in KBytes allowed unsigned long memory :// the memory in KBytes used by the domain unsigned short nrVirtCpu :// the number of virtual CPUs for the domain unsigned long long cpuTime : //the CPU time used in nanoseconds } If a domain is assigned to 4 vcpus and my machine has 6 physical cores, then the cpuTime in virDomainInfo should be the sum of cpu time of the 4 vcpus. When I want to calculate the cpu usage, which of the following is more accurate? 1/4 * cpu time / total time or 4/6 * cpu time / total time or just cpu time / total time regardszhangzhang