[libvirt-users] virsh dominfo does not show correct cpuTime

Hi, I am doing some domain resource monitoring work. I use cat /dev/urandom | md5sum to simulate vCPU load and write a script to calculate vCPU utilization. It seems all good at the beginning. After I abort the ``cat ... md5sum`` command in domain, I see some strange data as below: CPU time: 8410960000000 CPU util: 99.8410609331% CPU time: 8411970000000 CPU util: 100.843672381% CPU time: 8412380000000 CPU util: 40.9336949531% CPU time: 8412440000000 CPU util: 5.9899303915% *CPU time: 8412440000000* *CPU util: 0.0%* CPU time: 8412490000000 CPU util: 4.99165856007% *CPU time: 8412490000000* *CPU util: 0.0%* *CPU time: 8412490000000* *CPU util: 0.0%* CPU time: 8412570000000 CPU util: 7.987195515% *CPU time: 8412570000000* *CPU util: 0.0%* CPU time: 8412590000000 CPU util: 1.99668576091% CPU time: 8412670000000 CPU util: 7.98700539474% CPU time: 8412720000000 CPU util: 4.99167281754% CPU time: 8412780000000 CPU util: 5.98888552548% Looking at those 0.0% lines. Strange, though the guest is running, cpuTime does not increase. How can this happen? Any one helps? Thanks. Host information: - CentOS Linux release 7.0.1406 (Core) - libvirt 1.2.8 - qemu-kvm-rhev 2.1.2 ----- python script to capture cpu domain usage ---- import libvirt import time conn = libvirt.openReadOnly("qemu:///system") dom = conn.lookupByName('cpu-test') last_time = time.time() last_cpu_time = dom.info()[4] while True: time.sleep(1) this_time = time.time() dom_info = dom.info() print "CPU time: %s" % dom_info[4] print "CPU util: %s%%" % ((dom_info[4] - last_cpu_time) / ((this_time - last_time) * 10000000)) last_cpu_time = dom_info[4] last_time = this_time ----------------------------- end -----------------------------