2010/11/3 Sherif Nagy <sherif.nagy(a)gmail.com&gt;: Sorry for the late response. This site [1] is intended to show what's supported for each hypervisor, but unfortunately it's not very well maintained :( vcpuinfo is currently not implemented for the ESX driver as I don't see a way how to do it. To support it the ESX driver has to fill out this struct. struct _virVcpuInfo { unsigned int number; /* virtual CPU number */ int state; /* value from virVcpuState */ unsigned long long cpuTime; /* CPU time used, in nanoseconds */ int cpu; /* real CPU number, or -1 if offline */ }; There are several problems with it. ESX doesn't allow to specify or lookup a virtual CPU to physical CPU mapping (you can restrict the physical CPUs allowed for a guest). Therefore, the number and cpu members cannot be filled. The state member would always be VIR_VCPU_RUNNING, as there is no way to set single cores to offline and ESX doesn't tell you if a virtual CPU is blocked. The cpuTime member is another problem. libvirt exposes this as an absolute value since boot of the domain. ESX exposes this information relative in 20 seconds slots with 1 hour history. There is no way to get the absolute used CPU time from this. There might be possibilities to estimate values for this that are good enough for virt-top's CPU usage calculations. [1] http://libvirt.org/hvsupport.html Matthias