I was getting vCPU use time outside of guest with libvirt-python API, and them calculate utilization with (cpuTime2 - cpuTime1) / (t2 - t1). I was not doing this inside the guest os. 2015-07-24 15:09 GMT+08:00 2020human <human2020@qq.com>:

You calculate is vCPU use time not utilization。

use_time/total_cpu_time is utilization。

total_cpu_time=`cat /proc/stat |sed -n '1p'|awk '{ print sum=$2+$3+$4+$5+$6+$7+$8+$9+$10}'`

------------------ 原始邮件 ------------------ *发件人:* "changqian zuo";<zuochangqian@gmail.com>; *发送时间:* 2015年7月24日(星期五) 中午1:51 *收件人:* "libvirt-users"<libvirt-users@redhat.com>; *主题:* [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 -----------------------------